2,4-Disubstituted-5-thiazolecarboxylic acids and derivatives

ABSTRACT

2,4-Disubstituted-5-thiazolecarboxylic acids and derivatives thereof have been found to reduce herbicidal injury of corn, rice and sorghum plants due to the application thereto of acetamide herbicides.

This invention relates to novel 2,4-disubstituted-5-thiazolecarboxylic acids and derivatives thereof as well as their use in compositions and methods for reducing herbicidal injury. More specifically, the invention relates to novel compositions and methods for reducing injury to crop plants by herbicides, such as acetamides, especially acetanilides, which comprises treating the crop plant locus or the seed of the crop plant with an effective amount of a 2,4-disubstituted-5-thiazolecarboxylic acid or derivative thereof that will be described more fully below.

BACKGROUND OF THE INVENTION

Acetamide herbicides are very useful for controlling certain weeds, especially grasses, in the presence of growing crops. However, many of the acetamide herbicides injure certain crop plants slowing growth and development at application rates necessary to stunt or kill the weeds. Accordingly, some of the acetamide herbicides cannot be used for controlling weeds in the presence of certain crops. Obviously, a safening agent consisting of a composition that could be used to treat the seed of the crop plant, the crop plant locus or the crop plant itself, resulting in a reduction of injury due to application of the herbicide without a corresponding reduction of herbicidal action on the weed, would be quite beneficial.

DESCRIPTION OF THE INVENTION

In accordance with the novel aspects of the present invention, injury to crop plants, such as corn, rice and sorghum, due to application thereto of acetamide, herbicides, especially acetanilide herbicides such as 2-chloro-2',6'-diethyl-N-(methoxymethyl)acetanilide (hereinafter referred to by its common name, alachlor), 2-chloro-2',6'-diethyl-N-(butoxymethyl)acetanilide (hereinafter referred to by its common name, butachlor), 2-chloro-N-isopropylacetanilide (hereinafter referred to by its common mane, propachlor), N-(ethoxymethyl)-N-(2-ethyl-6-methyl-1-cyclohexen-1-yl)-2-chloroacetamide, N-(ethoxymethyl)-N-(2,5-dimethyl-1-cyclopenten-1-yl)-2-chloroacetamide, 2-chloro-N-(2-methoxy-1-methylethyl)-6'-ethyl-o-acetotoluidide and 2-chloro-N-(ethoxymethyl)-6'-ethyl-o-acetotoluidide, may be reduced without a corresponding reduction in injury to the weeds by application to the crop plant locus or the seed of the crop plant prior to planting of an effective amount of a safening agent comprising a 2,4-disubstituted-5-thiazolecarboxylic acid or derivative thereof having the formula ##STR1## wherein n is zero or one; X is selected from the group consisting of chloro, bromo, iodo, lower alkoxy, phenoxy and phenoxy substituted by one or two groups independently selected from the group consisting of lower alkyl and halogen; R is selected from the group consisting of alkyl having up to nine carbon atoms, haloalkyl and trialkoxymethyl; when n is one, R' is selected from the group consisting of hydrogen, agriculturally acceptable cations, alkyl (1-10 carbon atoms being preferred), lower alkenyl, lower alkynyl, lower alkoxy lower alkyl, haloalkyl, benzyl, phenyl and phenyl substituted by one or two members selected from the group consisting of halogen, lower alkyl, trifluoromethyl and nitro; when n is zero, R' is selected from the group consisting of chloro, amino and mono- or dilower alkylamino.

All of the compounds of the above formula are believed to be novel except those in which R is alkyl.

As used herein, the terms "lower alkyl", lower alkoxy "lower alkenyl" and "lower alkynyl" are understood to include alkyl, alkenyl and alkynyl groups having up to five carbon atoms, inclusive.

The terms "alkyl", "alkenyl" and "alkynyl" are understood to include branched and unbranched groups. When R' is lower alkenyl, allyl is preferred. When R' is lower alkynyl, propargyl is preferred.

The term "haloalkyl" is understood to mean those alkyl moieties having up to five carbon atoms wherein at least one hydrogen atom has been replaced by a halogen atom. Specifically included are those alkyl moieties in which all of the hydrogen atoms have been replaced by halogen atoms, such as trifluoromethyl.

The term "agriculturally acceptable cations" is understood to mean those cations that are commonly used to form the salt of the free acid. Such cations include, but are not limited to, alkali metal, alkaline earth, substituted amine and ammonium cations.

The amount of safening agent employed in the method and compositions of the invention will vary depending upon the particular herbicide with which the agent is employed, the rate of application of the herbicide, the crop to be protected as well as the manner of application of the safening agent. In each instance, the amount employed is a safening effective amount, i.e., the amount which reduces crop injury by the acetamide herbicide.

The safening agent may be applied to the plant locus in a mixture with the herbicide sequentially or it may be applied directly to the seed of the crop plant. By application to the "plant locus" is meant application to the plant growing medium, such as the soil, as well as the seeds, emerging seedlings, roots, stems, leaves, flowers, fruits or other plant parts.

The amount of herbicide employed is well within the skill of the art and is disclosed in various patents. Propachlor and its herbicidal use is disclosed in U.S. Pat. No. 2,863,752 and No. Reissue 26,961. Alachlor, butachlor and 2-chloro-N-(ethoxymethyl)-6'-ethyl-o-acetotoluidide and their herbicidal use are disclosed in U.S. Pat. Nos. 3,442,945 and 3,547,620. U.S. Pat. No. 3,937,730 discloses and claims 2-chloro-N-(2-methoxy-1-methylethyl)-6'-ethyl-o-acetotoluidide. The herbicidal use of N-(ethoxymethyl)-N-(2-ethyl-6-methyl-1-cyclohexen-1-yl)-2-chloroacetamide and N-(ethoxymethyl)-N-(2,5-dimethyl-1-cyclopenten-1-yl)-2-chloroacetamide is disclosed in Application Ser. No. 897,472, filed Apr. 18, 1978 by John P. Chupp now abandoned.

To illustrate the effectiveness of the 2,4-disubstituted-5-thiazolecarboxylic acids and derivatives thereof, the following examples are presented. These examples are presented merely as being illustrative of the novel aspects of the invention and are not intended to be a limitation as to the scope thereof.

EXAMPLE 1

A good grade of top soil is placed in a container and compacted to a depth of approximately 1.27 cm. from the top of said container. A predetermined number of seeds of each of the crop species to be tested are placed on top of the soil. A quantity of soil sufficient to substantially fill the container is measured and placed in a second container. A measured quantity of the safening agent dispersed or dissolved in a suitable carrier is applied to the soil in the second container. A measured quantity of the acetamide herbicide dispersed or dissolved in a suitable carrier is then sprayed on the soil already treated with the safening agent. The soil containing the safening agent and herbicide is thoroughly mixed. This mixing is sometimes referred to as incorporation of the herbicide and safening agent into the soil. The mixing or incorporation provides a substantially uniform distribution of the safening agent and herbicide throughout the soil. The seeds are covered with the soil containing the safening agent and acetamide herbicide and the pots are leveled. The pots are then placed on a sand bench in the greenhouse and watered from below as needed. The plants are observed at the end of approximately 21 days and the results in terms of percent inhibition of each seed lot are recorded. For each test series, a pot is also prepared containing no acetamide herbicide and no safening agent as a control. Additionally, for each test, pots are prepared with soil covering the seed containing no acetamide herbicide and only the measured amount of safening agent being incorporated into the soil covering the seeds to ascertain any herbicidal effect of the safening agent alone. For each series of tests, the herbicidal effect of the acetamide herbicide is observed from pots treated with the same quantity of herbicide alone. The "safening effect" is determined by adding the herbicidal effect of the acetamide herbicide when applied alone to the herbicidal effect of the safening agent when applied alone (in no instance, however, will this sum be greater than 100) and substracting from that the herbicidal effect obtained when both the herbicide and safening agent are incorporated into the soil as discussed above.

Table I summarizes the results obtained when the compounds of the invention were tested in accordance with the procedure of Example 1 utilizing alachlor as the herbicide.

                                      Table I                                      __________________________________________________________________________                       Rate of                                                                               Rate of                                                                 Safening                                                                              Herbicide  Safening                                   Safening Agent    Agent (kg/h)                                                                          (kg/h)                                                                               Crop Effect                                     __________________________________________________________________________     Ethyl 2-chloro-4-isopropyl-5-                                                                    8.96   4.48  sorghum                                                                             60                                         thiazolecarboxylate                                                                              8.96   4.48  rice 20                                         Ethyl 2-chloro-4-ethyl-5-                                                                        8.96   4.48  sorghum                                                                             64                                         thiazolecarboxylate                                                                              8.96   4.48  rice 25                                         Ethyl 2-chloro-4-trifluoromethyl-                                                                8.96   4.48  sorghum                                                                             65                                         5-thiazolecarboxylate                                                                            8.96   4.48  rice *                                          Ethyl 2-chloro-4-t-butyl-5-                                                                      8.96   4.48  sorghum                                                                             75                                         thiazolecarboxylate                                                                              8.96   4.48  rice *                                          Butyl 2-chloro-4-trifluoromethyl-                                                                8.96   2.24  sorghum                                                                             53                                         5-thiazolecarboxylate                                                                            8.96   2.24  rice 58                                         Hexyl 2-chloro-4-trifluoromethyl-                                                                8.96   2.24  sorghum                                                                             43                                         5-thiazolecarboxylate                                                                            8.96   2.24  rice 33                                         Octyl 2-chloro-4-trifluoromethyl-                                                                8.96   2.24  sorghum                                                                             38                                         5-thiazolecarboxyate                                                                             8.96   2.24  rice 23                                         Phenyl 2-chloro-4-trifluoro-                                                                     8.96   2.24  sorghum                                                                             30                                         methy-5-thiazolecarboxylate                                                                      8.96   2.24  rice *                                          p-Chlorophenyl 2-chloro-4-trifluoro-                                                             8.96   2.24  sorghum                                                                             30                                         methyl-5-thiazolecarboxylate                                                                     8.96   2.24  rice 20                                         Ethyl 2-phenoxy-4-trifluoro-                                                                     8.96   2.24  sorghum                                                                             55                                         methyl-5-thiazolecarboxylate                                                                     8.96   2.24  rice 30                                         Ethyl 2-ethoxy-4-triethoxy-                                                                      8.96   2.24  sorghum                                                                             55                                         methyl-5-thiazolecarboxylate                                                                     8.96   2.24  rice 70                                         Allyl 2-chloro-4-trifluoro-                                                                      8.96   2.24  sorghum                                                                             55                                         methyl-5-thiazolecarboxylate                                                                     8.96   2.24  rice 70                                         2-Chloro-4-trifluoromethyl-                                                                      8.96   2.24  sorghum                                                                             70                                         5-thiazolecarboxylic acid                                                                        8.96   rice  *                                               Methyl 2-chloro-4-trifluoro-                                                                     8.96   2.24  sorghum                                                                             40                                         methyl-5-thiazolecarboxylate                                                                     8.96   2.24  rice *                                          Isoropyl 2-chloro-4-trifluoro-                                                                   8.96   2.24  sorghum                                                                             75                                         methyl-5-thiazolecarboxylate                                                                     8.96   2.24  rice *                                          Benzyl 2-chloro-4-trifluoro-                                                                     8.96   2.24  sorghum                                                                             50                                         methyl-5-thiazolecarboxylate                                                                     8.96   2.24  rice *                                          Butoxyethyl 2-chloro-4-trifluoro-                                                                8.96   2.24  sorghum                                                                             65                                         methyl-5-thiazolecarboxylate                                                                     8.96   2.24  rice 28                                         β-trichloroethyl 2-chloro-4-tri-                                                            8.96   2.24  sorghum                                                                             70                                         fluoromethyl-5-thiazolecarboxylate                                                               8.96   2.24  rice *                                          Methyl 2-chloro-4-heptafluoro-                                                                   4.48   2.24  sorghum                                                                             20                                         ropyl-5-thiazolecarboxylate                                                                      4.48   2.24  rice *                                          Ethyl 2-chloro-4-pentafluoro-                                                                    8.96   2.24  sorghum                                                                             55                                         ethyl-5-thiazolecarboxylate                                                                      8.96   2.24  rice 63                                         Ethyl 2-bromo-4-trifluoro-                                                                       8.96   2.24  sorghum                                                                             40                                         methyl-5-thiazolecarboxylate                                                                     8.96   2.24  rice 75                                         Ethyl 2-iodo-4-trifluoro-                                                                        8.96   4.48  sorghum                                                                             40                                         methyl-5-thiazolecarboxylate                                                                     8.96   4.48  rice 20                                         2-Chloro-4-trifluoromethyl-                                                                      8.96   4.48  sorghum                                                                             40                                         5-thiazolecarboxylic acid chloride                                                               8.96   4.48  rice *                                          N,N-diethyl-2-chloro-4-trifluoro-                                                                8.96   4.48  sorghum                                                                             23                                         methyl-5-thiazolecarboxamide                                                                     8.96   4.48  rice 25                                         Ethyl 2-chloro-4-trichloro-                                                                      8.96   4.48  sorghum                                                                             *                                          methyl-5-thiazolecarboxylate                                                                     8.96   4.48  rice 25                                         Triethanolamine salt of 2-chloro-                                                                8.96   2.24  sorghum                                                                             57                                         4-trifluoromethyl-5-thiazolecar-                                                                 8.96   2.24  rice *                                          boxylic acid                                                                   Ethyl 2-fluoro-4-trifluoro-                                                                      8.96   2.24  sorghum                                                                             *                                          methyl-5-thiazolecarboxylate                                                                     8.96   2.24  rice *                                          Diethylamine satl of 2-chloro-                                                                   8.96   2.24  sorghum                                                                             22                                         4-trifluoromethyl-5-thiazole-                                                                    8.96   2.24  rice *                                          carboxylic acid                                                                Isoropylamine salt of 2-                                                                         8.96   2.24  sorghum                                                                             42                                         chloro-4-trifluoromethyl-5-                                                                      8.96   2.24  rice *                                          thiazolecarboxylic acid                                                        Ethyl 2-chloro-4-trifluoro-                                                                      8.96   0.56  sorghum                                                                             93                                         methyl-5-thiazolecarboxylate                                                                     8.96   1.12  sorghum                                                                             95                                                           8.96   2.24  sorghum                                                                             87                                                           8.96   4.48  sorghum                                                                             75                                                           8.96   0.56  rice 53                                                           8.96   1.12  rice 25                                                           8.96   2.24  rice 25                                                           8.96   4.48  rice 35                                         Ethyl 2-chloro-4-isopropyl-                                                                      8.96   0.56  sorghum                                                                             90                                         5-thiazolecarboxylate                                                                            8.96   1.12  sorghum                                                                             85                                                           8.96   2.24  sorghum                                                                             70                                                           8.96   4.48  sorghum                                                                             55                                                           8.96   0.56  rice 65                                                           8.96   1.12  rice 64                                                           8.96   2.24  rice *                                                            8.96   4.48  rice 25                                         Ethyl 2-chloro-4-ethyl-4-                                                                        8.96   0.56  sorghum                                                                             80                                         thiazolecarboxylate                                                                              8.96   1.12  sorghum                                                                             58                                                           8.96   2.24  sorghum                                                                             57                                                           8.96   4.48  sorghum                                                                             24                                                           8.96   0.56  rice 80                                                           8.96   1.12  rice 84                                                           8.96   2.24  rice *                                                            8.96   4.48  rice *                                          Ethyl 2-chloro-4-t-butyl-                                                                        8.96   0.56  sorghum                                                                             99                                         5-thiazolecarboxylate                                                                            8.96   1.12  sorghum                                                                             89                                                           8.96   2.24  sorghum                                                                             85                                                           8.96   4.48  sorghum                                                                             40                                                           8.96   0.56  rice 55                                                           8.96   1.12  rice 30                                                           8.96   2.24  rice 45                                                           8.96   4.48  rice *                                          Butyl 2-chloro-4-trifluoro-                                                                      8.96   0.56  sorghum                                                                             *                                          methyl-5-thiazolecarboxylate                                                                     8.96   1.12  sorghum                                                                             55                                                           8.96   2.24  sorghum                                                                             55                                                           8.96   4.48  sorghum                                                                             60                                                           8.96   0.56  rice 38                                                           8.96   1.12  rice 38                                                           8.96   2.24  rice *                                                            8.96   4.48  rice *                                          Hexyl 2-chloro-4-trifluoro-                                                                      8.96   0.56  sorghum                                                                             *                                          methyl-5-thiazolecarboxylate                                                                     8.96   1.12  sorghum                                                                             45                                                           8.96   2.24  sorghum                                                                             45                                                           8.96   4.48  sorghum                                                                             60                                                           8.96   0.56  rice 43                                                           8.96   1.12  rice 40                                                           8.96   2.24  rice 48                                                           8.96   4.48  rice *                                          Octyl 2-chloro-4-trifluoro-                                                                      8.96   0.56  sorghum                                                                             45                                         methyl-5-thiazolecarboxylate                                                                     8.96   1.12  sorghum                                                                             80                                                           8.96   2.24  sorghum                                                                             60                                                           8.96   4.48  sorghum                                                                             55                                                           8.96   0.56  rice 88                                                           8.96   1.12  rice 30                                                           8.96   2.24  rice 38                                                           8.96   4.48  rice 28                                         Ethyl 2-phenoxy-4-trifluoro-                                                                     8.96   0.56  sorghum                                                                             25                                         methyl-5-thiazolecarboxylate                                                                     8.96   1.12  sorghum                                                                             50                                                           8.96   2.24  sorghum                                                                             25                                                           8.96   4.48  sorghum                                                                             45                                                           8.96   0.56  rice 48                                                           8.96   1.12  rice 45                                                           8.96   2.24  rice *                                                            8.96   4.48  rice *                                          Ethyl 2-ethoxy-4-triethoxy-                                                                      8.96   0.56  sorghum                                                                             *                                          methyl-5-thiazolecarboxylate                                                                     8.96   1.12  sorghum                                                                             35                                                           8.96   2.24  sorghum                                                                             20                                                           8.96   4.48  sorghum                                                           8.96   0.56  rice                                                              8.96   1.12  rice *                                                            8.96   2.24  rice *                                                            8.96   4.48  rice *                                          Allyl 2-chloro-4-trifluoro-                                                                      8.96   0.56  sorghum                                                                             30                                         methyl-5-thiazolecarboxylate                                                                     8.96   1.12  sorghum                                                                             60                                                           8.96   2.24  sorghum                                                                             45                                                           8.96   4.48  sorghum                                                                             65                                                           8.96   0.56  rice 73                                                           8.96   1.12  rice 20                                                           8.96   2.24  rice 23                                                           8.96   4.48  rice *                                          Phenyl 2-chloro-4-trifluoro-                                                                     8.96   0.56  sorghum                                                                             75                                         methyl-5-thiazolecarboxylate                                                                     8.96   1.12  sorghum                                                                             60                                                           8.96   2.24  sorghum                                                                             65                                                           8.96   4.48  sorghum                                                                             60                                                           8.96   0.56  rice 58                                                           8.96   1.12  rice 32                                                           8.96   2.24  rice 20                                                           8.96   4.48  rice *                                          p-Chlorophenyl 2-chloro-4-                                                                       8.96   0.56  sorghum                                                                             75                                         trifluoromethyl-5-thiazole-                                                                      8.96   1.12  sorghum                                                                             70                                         carboxylate       8.96   2.24  sorghum                                                                             65                                                           8.96   4.48  sorghum                                                                             65                                                           8.96   0.56  rice 43                                                           8.96   1.12  rice 32                                                           8.96   2.24  rice 25                                                           8.96   4.48  rice *                                          Isopropyl 2-chloro-4-trifluoro-                                                                  8.96   0.56  sorghum                                                                             55                                         methyl-5-thiazolecarboxylate                                                                     8.96   1.12  Sorghum                                                                             47                                                           8.96   2.24  sorghum                                                                             40                                                           8.96   4.48  sorghum                                                                             28                                                           8.96   0.56  rice 75                                                           8.96   1.12  rice 50                                                           8.96   2.24  rice 20                                                           8.96   4.48  rice *                                          β-trichloroethyl 2-chloro-4-                                                                8.96   0.56  sorghum                                                                             60                                         trifluoromethyl-5-thiazole-                                                                      8.96   1.12  sorghum                                                                             57                                         carboxylate       8.96   2.24  sorghum                                                                             55                                                           8.96   4.48  sorghum                                                                             40                                                           8.96   0.56  rice 50                                                           8.96   1.12  rice 50                                                           8.96   2.24  rice 35                                                           8.96   4.48  rice *                                          Ethyl 2-bromo-4-trifluoro-                                                                       8.96   0.56  sorghum                                                                             73                                         methyl-5-thiazolecarboxylate                                                                     8.96   1.12  sorghum                                                                             70                                                           8.96   2.24  sorghum                                                                             65                                                           8.96   4.48  sorghum                                                                             65                                                           8.96   0.56  rice 60                                                           8.96   1.12  rice 60                                                           8.96   2.24  rice 45                                                           8.96   4.48  rice 20                                         Ethyl 2-iodo-4-trifluromethyl-                                                                   8.96   0.56  sorghum                                                                             80                                         5-thiazolecarboxylate                                                                            8.96   1.12  sorghum                                                                             75                                                           8.96   2.24  sorghum                                                                             75                                                           8.96   4.48  sorghum                                                                             78                                                           8.96   0.56  rice 34                                                           8.96   1.12  rice 36                                                           8.96   2.24  rice *                                                            8.96   4.48  rice 23                                         2-Chloro-4-trifluoromethyl-5-                                                                    8.96   0.56  sorghum                                                                             80                                         thiazolecarboxylic acid chloride                                                                 8.96   1.12  sorghum                                                                             60                                                           8.96   2.24  sorghum                                                                             *                                                            8.96   4.48  sorghum                                                                             *                                                            8.96   0.56  rice *                                                            8.96   1.12  rice *                                                            8.96   2.24  rice *                                                            8.96   4.48  rice *                                          N,N-diethyl-2-chloro-4-tri-                                                                      8.96   0.56  sorghum                                                                             25                                         fluoromethyl-5-thiazole-                                                                         8.96   1.12  sorghum                                                                             *                                          carboxamide       8.96   2.24  sorghum                                                                             *                                                            8.96   4.48  sorghum                                                                             *                                                            8.96   0.56  rice 45                                                           8.96   1.12  rice *                                                            8.96   2.24  rice *                                                            8.96   4.48  rice *                                          Ethyl 2-chloro-4-trichloro-                                                                      8.96   0.56  sorghum                                                                             45                                         methyl-5-thiazolecarboxylate                                                                     8.96   1.12  sorghum                                                                             *                                                            8.96   2.24  sorghum                                                                             *                                                            8.96   4.48  sorghum                                                                             *                                                            8.96   0.56  rice 75                                                           8.96   1.12  rice 55                                                           8.96   2.24  rice 45                                                           8.96   4.48  rice 50                                         Methyl 2-chloro-4-trifluoro-                                                                     8.96   0.56  sorghum                                                                             80                                         methyl-5-thiazolecarboxylate                                                                     8.96   1.12  sorghum                                                                             75                                                           8.96   2.24  sorghum                                                                             70                                                           8.96   4.48  sorghum                                                                             73                                                           8.96   0.56  rice *                                                            8.96   1.12  rice *                                                            8.96   2.24  rice 28                                                           8.96   4.48  rice 38                                         Benzyl 2-chloro-4-trifluoro-                                                                     8.96   0.56  sorghum                                                                             90                                         methyl-5-thiazolecarboxylate                                                                     8.96   1.12  sorghum                                                                             100                                                          8.96   2.24  sorghum                                                                             80                                                           8.96   4.48  sorghum                                                                             75                                                           8.96   0.56  rice 44                                                           8.96   1.12  rice 26                                                           8.96   2.24  rice *                                                            8.96   4.48  rice *                                          Butoxyethyl 2-chloro-4-trifluoro-                                                                8.96   0.56  sorghum                                                                             80                                         methyl-5-thiazolecarboxylate                                                                     8.96   1.12  sorghum                                                                             85                                                           8.96   2.24  sorghum                                                                             80                                                           8.96   4.48  sorghum                                                                             70                                                           8.96   0.56  rice 39                                                           8.96   1.12  rice 26                                                           8.96   2.24  rice *                                                            8.96   4.48  rice 23                                         β-chloroethyl 2-chloro-4-trifluoro-                                                         8.96   0.56  sorghum                                                                             80                                         methyl-5-thiazolecarboxylate                                                                     8.96   1.12  sorghum                                                                             70                                                           8.96   2.24  sorghum                                                                             70                                                           8.96   4.48  sorghum                                                                             70                                                           8.96   0.56  rice 34                                                           8.96   1.12  rice 26                                                           8.96   2.24  rice *                                                            8.96   4.48  rice *                                          2-Chloro-4-trifluoromethyl-                                                                      8.96   0.56  sorghum                                                                             68                                         5-thiazolecarboxylic acid                                                                        8.96   1.12  sorghum                                                                             73                                                           8.96   2.24  sorghum                                                                             51                                                           8.96   4.48  sorghum                                                                             43                                                           8.96   0.56  rice 55                                                           8.96   1.12  rice 35                                                           8.96   2.24  rice *                                                            8.96   4.48  rice *                                          Ethyl 2-chloro-4-pentafluoro-                                                                    8.96   0.56  sorghum                                                                             25                                         ethyl-5-thiazolecarboxylate                                                                      8.96   1.12  sorghum                                                                             65                                                           8.96   2.24  sorghum                                                                             50                                                           8.96   4.48  sorghum                                                                             48                                                           8.96   0.56  rice *                                                            8.96   1.12  rice 25                                                           8.96   2.24  rice 35                                                           8.96   4.48  rice 30                                         __________________________________________________________________________      *Safening effect was between 0 and 20                                    

Table II summarizes the results obtained when the compounds of the invention were tested in accordance with the procedure of Example I utilizing butachlor as the herbicide.

                                      Table II                                     __________________________________________________________________________                      Rate of                                                                               Rate of                                                                 Safening                                                                              Herbicide                                                                            Safening                                         Safening Agent   Agent (kg/h)                                                                          Crop  Effect                                           __________________________________________________________________________     Ethyl 2-chloro-4-isopropyl-                                                                     8.96   4.48  sorghum                                                                             60                                          5-thiazolecarboxylate                                                                           8.96   4.48  rice 33                                          Ethyl 2-chloro-4-ethyl-5-                                                                       8.96   4.48  sorghum                                                                             60                                          thiazolecarboxylate                                                                             8.96   4.48  rice 70                                          Ethyl 2-chloro-4-trifluoro-                                                                     8.96   4.48  sorghum                                                                             75                                          methyl-5-thiazolecarboxylate                                                                    8.96   4.48  rice 20                                          Ethyl 2-chloro-4-t-butyl-                                                                       8.96   4.48  sorghum                                                                             28                                          5-thiazolecarboxylate                                                                           8.96   4.48  rice 70                                          Butyl 2-chloro-4-trifluoro-                                                                     8.96   4.48  sorghum                                                                             40                                          methyl-5-thiazolecarboxylate                                                                    8.96   4.48  rice 62                                          Hexyl 2-chloro-4-trifluoro-                                                                     8.96   4.48  sorghum                                                                             40                                          methyl-5-thiazolecarboxylate                                                                    8.96   4.48  rice 47                                          Octyl 2-chloro-4-trifluoro-                                                                     8.96   4.48  sorghum                                                                             40                                          methyl-5-thiazolecarboxylate                                                                    8.96   4.48  rice 37                                          Phenyl 2-chloro-4-trifluoro-                                                                    8.96   4.48  sorghum                                                                             *                                           methyl-5-thiazolecarboxylate                                                                    8.96   4.48  rice 55                                          p-Chlorophenyl 2-chloro-4-tri-                                                                  8.96   4.48  sorghum                                                                             20                                          fluoromethyl-5-thiazolecarboxylate                                                              8.96   4.48  rice 55                                          Ethyl 2-phenoxy-4-trifluoro-                                                                    8.96   4.48  sorghum                                                                             28                                          methyl-5-thiazolecarboxylate                                                                    8.96   4.48  rice 68                                          Ethyl 2-ethoxy-4-triethoxy-                                                                     8.96   4.48  sorghum                                                                             28                                          methyl-5-thiazolecarboxylate                                                                    8.96   4.48  rice 50                                          Allyl 2-chloro-4-trifluoro-                                                                     8.96   4.48  sorghum                                                                             *                                           methyl-5-thiazolecarboxylate                                                                    8.96   4.48  rice 50                                          2-Chloro-4-trifluoromethyl-                                                                     8.96   4.48  sorghum                                                                             62                                          5-thiazolecarboxylic acid                                                                       8.96   4.48  rice 68                                          Methyl 2-chloro-4-trifluoro-                                                                    8.96   4.48  sorghum                                                                             62                                          methyl-5-thiazolecarboxylate                                                                    8.96   4.48  rice 53                                          Isoropyl 2-chloro-4-trifluoro-                                                                  8.96   4.48  sorghum                                                                             37                                          methyl-5-thiazolecarboxylate                                                                    8.96   4.48  rice *                                           Benzyl 2-chloro-4-trifluoromethyl-                                                              8.96   4.48  sorghum                                                                             22                                          5-thiazolecarboxylate                                                                           8.96   4.48  rice 57                                          Butoxyethyl 2-chloro-4-trifluoro-                                                               8.96   4.48  sorghum                                                                             67                                          methyl-5-thiazolecarboxylate                                                                    8.96   4.48  rice 57                                          β-trichloroethyl 2-chloro-4-tri-                                                           8.96   4.48  sorghum                                                                             32                                          fluoromethyl-5-thiazolecarboxylate                                                              8.96   4.48  rice 27                                          Methyl 2-chloro-4-heptafluoro-                                                                  8.96   4.48  sorghum                                                                             *                                           propyl-5-thiazolecarboxylate                                                                    8.96   4.48  rice 59                                          Ethyl 2-chloro-4-pentafluoro-                                                                   8.96   4.48  sorghum                                                                             *                                           ethyl-5-thiazolecarboxylate                                                                     8.96   4.48  rice 45                                          Ethyl 2-bromo-4-trifluoro-                                                                      8.96   4.48  sorghum                                                                             *                                           methyl-5-thiazolecarboxylate                                                                    8.96   4.48  rice 70                                          Ethyl 2-iodo-4-trifluoromethyl-                                                                 8.96   6.72  sorghum                                                                             23                                          5-thiazolecarboxylate                                                                           8.96   6.72  rice 47                                          2-Chloro-4-trifluoromethyl-5-                                                                   8.96   6.72  sorghum                                                                             *                                           thiazolecarboxylic acid chloride                                                                8.96   6.72  rice *                                           N,N-diethyl-2-chloro-4-trifluoro-                                                               8.96   6.72  sorghum                                                                             45                                          methyl-5-thiazolecarboxamide                                                                    8.96   6.72  rice 70                                          Ethyl 2-chloro-4-trichloromethyl-                                                               8.96   6.72  sorghum                                                                             33                                          5-thiazolecarboxylate                                                                           8.96   6.72  rice 30                                          Triethanolamine salt of 2-chloro-4-                                                             8.96   6.72  sorghum                                                                             20                                          trifluoromethyl-5-thiazolecarboxylic                                                            8.96   6.72  rice *                                           acid                                                                           Diethylamine salt of 2-chloro-                                                                  8.96   6.72  sorghum                                                                             40                                          4-trifluoromethyl-5-thiazole-                                                                   8.96   6.72  rice *                                           carboxylic acid                                                                Isoropylamine salt of 2-chloro-                                                                 8.96   6.72  sorghum                                                                             35                                          4-trifluoromethyl-5-thiazole-                                                                   8.96   6.72  rice 20                                          carboxylic acid                                                                Ethyl 2-fluoro-4-trifluoromethyl-                                                               8.96   6.72  sorghum                                                                             *                                           5-thiazolecarboxylate                                                                           8.96   6.72  rice 30                                          __________________________________________________________________________      *Safening effect was between 0 and 20                                    

EXAMPLE 2

A good grade of top soil is placed in a plastic pot. A measured quantity of the safening agent dispersed or dissolved in a suitable carrier is sprayed on the soil surface. A measured quantity of butachlor herbicide dissolved in a solvent is sprayed on the soil surface. Pre-soaked rice is seeded into the pots that were previously flooded with water. The pots are flooded at least up to the soil surface for the duration of the test. The plants are observed at the end of approximately 21 days and the results in terms of the percent inhibition of rice are recorded. As in Example 1, for each test pots are prepared containing soil treated only with butachlor. For each test, pots are also prepared containing soil treated only with the safening agent. The safening effect is determined in accordance with Example 1.

Table II summarizes the results obtained when the compounds of the invention were tested in accordance with the procedure of Example 2.

                                      Table III                                    __________________________________________________________________________                      Rate of                                                                               Rate of                                                                 Safening                                                                              Herbicide                                                                            Safening                                         Safening Agent   Agent (kg/h)                                                                          (kg/h)                                                                               Effect                                           __________________________________________________________________________     Ethyl 2-chloro-4-t-butyl-5-                                                                     1.12   0.14  34                                               thiazolecarboxylate                                                                             1.12   0.56  *                                                Butyl 2-chloro-4-trifluoro-                                                                     0.56   0.07  *                                                methyl-5-thiazolecarboxylate                                                                    0.56   0.28  25                                                                0.56   1.12  *                                                Hexyl 2-chloro-4-trifluoro-                                                                     0.56   0.07  *                                                methyl-5-thiazolecarboxylate                                                                    0.56   0.28  25                                               Octyl 2-chloro-4-trifluoro-                                                                     0.56   0.07  24                                               methyl-5-thiazolecarboxylate                                                                    0.56   0.28  53                                                                0.56   1.12  30                                               Phenyl 2-chloro-4-trifluoro-                                                                    0.56   0.07  30                                               methyl-5-thiazolecarboxylate                                                                    0.56   0.28  61                                                                0.56   1.12  30                                               p-Chlorophenyl 2-chloro-4-tri-                                                                  0.56   0.07  29                                               fluoromethyl-5-thiazolecarboxylate                                                              0.56   0.28  42                                                                0.56   1.12  25                                               Ethyl 2-phenoxy-4-trifluoro-                                                                    0.56   0.07  *                                                methyl-5-thiazolecarboxylate                                                                    0.56   0.28  35                                                                0.56   1.12  *                                                Ethyl 2-ethoxy-4-triethoxy-                                                                     0.56   0.07  *                                                methyl-5-thiazolecarboxylate                                                                    0.56   0.28  *                                                                 0.56   1.12  *                                                Allyl 2-chloro-4-trifluoro-                                                                     0.56   0.07  *                                                methyl-5-thiazolecarboxylate                                                                    0.56   0.28  40                                                                0.56   1.12  *                                                Ethyl 2-chloro-4-ethyl-5-                                                                       1.12   0.14  *                                                thiazolecarboxylate                                                                             1.12   0.56  *                                                2-Chloro-4-trifluoromethyl-                                                                     0.56   0.07  36                                               5-thiazolecarboxylic acid                                                                       0.56   0.28  35                                                                0.56   1.12  *                                                Methyl 2-chloro-4-trifluoro-                                                                    0.56   0.07  44                                               methyl-5-thiazolecarboxylate                                                                    0.56   0.28  67                                                                0.56   1.12  *                                                Benzyl 2-chloro-4-trifluoro-                                                                    0.56   0.07  44                                               methyl-5-thiazolecarboxylate                                                                    0.56   0.28  75                                                                0.56   1.12  20                                               Butoxyethyl 2-chloro-4-trifluoro-                                                               0.56   0.07  46                                               methyl-5-thiazolecarboxylate                                                                    0.56   0.28  72                                                                0.56   1.12  *                                                β-chloroethyl 2-chloro-4-trifluoro-                                                        0.56   0.07  56                                               methyl-5-thiazolecarboxylate                                                                    0.56   0.28  75                                                                0.56   1.12  30                                               Ethyl 2-bromo-4-trifluoromethyl-                                                                0.56   0.07  *                                                5-thiazolecarboxylate                                                                           0.56   0.28  70                                                                0.56   1.12  32                                               Ethyl 2-iodo-4-trifluoro-                                                                       0.56   0.07  *                                                methyl-5-thiazolecarboxylate                                                                    0.56   0.28  50                                                                0.56   1.12  *                                                Ethyl 2-ethoxy-4-trifluoro-                                                                     0.56   0.07  *                                                methyl-5-thiazolecarboxylate                                                                    0.56   0.28  *                                                                 0.56   1.12  *                                                Ethyl 2-chloro-4-pentafluro-                                                                    0.56   0.07  40                                               ethyl-5-thiazolecarboxylate                                                                     0.56   0.28  24                                                                0.56   1.12  *                                                N,N-diethyl-2-chloro-4-trifluoro-                                                               0.56   0.07  35                                               methyl-5-thiazolecarboxamide                                                                    0.56   0.28  59                                                                0.56   1.12  *                                                __________________________________________________________________________      *Safening effect was between 0 and 20                                    

As noted previously, the 2,4-disubstituted-5-thiazolecarboxylates may be used to protect crops from the herbicidal activity of acetamide herbicides without a corresponding diminution in herbicidal activity to the weeds. Examples 3-6 are illustrative of such activity.

EXAMPLE 3

A good grade of top soil is placed in a plastic pot and compacted to a depth of approximately 1.27 cm. from the top of said pot. A predetermined number of crop seeds and weed seeds are placed on top of the soil. A cover layer, approximately 1.27 cm., is placed on top of said seeds. The soil is then treated with a mixture of the safening agent and alachlor dispersed or dissolved in a suitable solvent. For each test series, pots are treated with only the herbicide. Additionally, pots are treated with only the safening agent. The herbicidal effect is observed approximately 21 days after treatment.

Tables IV-IX summarize the results obtained when the compounds of the invention were tested in accordance with the procedure of Example 3. Each table represents the results of different tests using said procedure. Note that in each test a control is used in which the plants are treated with various rates of the herbicide alone.

                                      Table IV                                     __________________________________________________________________________     Rate of            Rate of                                                                               Percent Inhibition                                   Herbicide          Safening    Green                                                                              Crab-                                                                               Barnyard                               (kg/h)                                                                               Safening Agent                                                                              Agent (kg/h)                                                                          Sorghum                                                                             Foxtail                                                                            grass                                                                              Grass                                   __________________________________________________________________________      0.035                                                                               --           --      0    98 93   99                                     0.14                      33   100 99  100                                     0.56                      50   100 99  100                                     2.24                      95   100 100 100                                     --    Ethyl 2-chloro-4-isopropyl-                                                                 0.14    0    0   0   0                                       0.035                                                                               5-thiazolecarboxylate                                                                       0.14    0    95 97   93                                     0.14               0.14   10   100 99   99                                     0.56               0.14    8    99 99   99                                     2.24               0.14   93   100 100 100                                     --    Ethyl 2-chloro-4-isoropyl-                                                                  0.56    0    0   0   0                                       0.035                                                                               5-thiazolecarboxylate                                                                       0.56    0    99 99   97                                     0.14               0.56    3    99 99  100                                     0.56               0.56   20   100 99   99                                     2.24               0.56   68   100 100 100                                     --    Ethyl 2-chloro-4-isopropyl-                                                                 2.24    0    0   0   0                                       0.035                                                                               5-thiazolecarboxylate                                                                       2.24     0   99 93   97                                     0.14               2.24    3    98 99  100                                     0.56               2.24   25   100 99  100                                     2.24               2.24   78   100 100 100                                     __________________________________________________________________________

                                      Table V                                      __________________________________________________________________________     Rate of           Rate of                                                                               Percent Inhibition                                    Herbicide         Safening    Green                                                                              Crab-                                                                              Barnyard                                 (kg/h)                                                                               Safening Agent                                                                             Agent (kg/h)                                                                          Sorghum                                                                             Foxtail                                                                            grass                                                                              Grass                                    __________________________________________________________________________      0.035                                                                               --          --     10   83  92   91                                      0.14                     10   93  96   99                                      0.56                     35   99  99  100                                      2.24                     87   100 99  100                                      --    Ethyl 2-chloro-4-t-butyl-                                                                  0.14    3    0   3   0                                        0.035                                                                               5-thiazolecarboxylate                                                                      0.14    3   75  93   93                                      0.14              0.14   10   90  96   99                                      0.56              0.14   18   98  99   99                                      2.24              0.14   65   100 99  100                                      --    Ethyl 2-chloro-4-t-butyl-                                                                  0.56    3    0   0   0                                        0.035                                                                               5-thiazolecarboxylate                                                                      0.56    3   53  90   89                                      0.14              0.56    8   88  95  100                                      0.56              0.56   30   97  98  100                                      2.24              0.56   48   100 99  100                                      __________________________________________________________________________

                                      Table VI                                     __________________________________________________________________________     Rate of             Rate of                                                                               Percent Inhibition                                  Herbicide           Safening    Green                                                                              Crab-                                                                              Barnyard                               (kg/h)                                                                               Safening Agent                                                                               Agent (kg/h)                                                                          Sorghum                                                                             Foxtail                                                                            grass                                                                              Grass                                  __________________________________________________________________________      0.035                                                                               --            --     0    17  83  96                                     0.14                       32   70  97  98                                     0.56                       77   97  99  99                                     2.24                       92   98  99  100                                    --    Ethyl 2-chloro-4-trifluoro-                                                                  0.14   0     0   0   0                                      0.035                                                                               methyl-5-thiazolecarboxylate                                                                 0.14   0    25  83  75                                     0.14                0.14   10   68  99  99                                     0.56                0.14   3    90  99  100                                    2.24                0.14   40   100 99  100                                    --    Ethyl 2-chloro-4-trifluoro-                                                                  0.56   0     0   0   0                                     0.035 methyl-5-thiazolecarboxylate                                                                 0.56   0     8  70  78                                     0.14                0.56   0    73  99  97                                     0.56                0.56   5    93  99  99                                     2.24                0.56   15   100 100 100                                    --    Ethyl 2-chloro-4-trifluoro-                                                                  2.24   0     0   0   0                                      0.035                                                                               methyl-5-thiazolecarboxylate                                                                 2.24   0     3  40  40                                     0.14                2.24   0    58  90  99                                     0.56                2.24   5    92  100 100                                    2.24                2.24   5    99  100 100                                    __________________________________________________________________________

                                      Table VII                                    __________________________________________________________________________     Rate of             Rate of                                                                               Percent Inhibition                                  Herbicide           Safening    Green                                                                              Crab-                                                                              Barnyard                               (kg/h)                                                                               Safening Agent                                                                               Agent (kg/h)                                                                          Sorghum                                                                             Foxtail                                                                            grass                                                                              Grass                                  __________________________________________________________________________     0.14  --            --     63   95  93   99                                    0.56                       95   99  99  100                                    2.24                       99   100 99  100                                    --    Methyl 2-chloro-4-trifluoro-                                                                 0.14   10    0   0   0                                     0.14  methyl-5-thiazolecarboxylate                                                                 0.14   40   98  95   99                                    0.56                0.14   55   99  99  100                                    2.24                0.14   93   99  99  100                                    --    Methyl 2-chloro-4-trifluoro-                                                                 0.56    0    0   0   0                                     0.14  methyl-5-thiazolecarboxylate                                                                 0.56   13   97  98   98                                    0.56                0.56   55   99  99  100                                    2.24                0.56   73   99  99  100                                    --    Benzyl 2-chloro-4-trifluoro-                                                                 0.14    0    0   0   0                                     0.14  methyl-5-thiazolecarboxylate                                                                 0.14   55   97  93   98                                    0.56                0.14   65   99  99  100                                    2.24                0.14   88   100 99  100                                    --    Benzyl 2-chloro-4-trifluoro-                                                                 0.56    0    0   0   0                                     0.14  methyl-5-thiazolecarboxylate                                                                 0.56   35   95  95   99                                    0.56                0.56   58   99  99  100                                    2.24                0.56   88   99  99  100                                    --    Butoxyethyl 2-chloro-4-tri-                                                                  0.14    0    0   0   0                                     0.14  fluoromethyl-5-thiazole-                                                                     0.14   28   97  97  100                                    0.56  carboxylate   0.14   70   99  99  100                                    2.24                0.14   90   100 99  100                                    --    Butoxyethyl 2-chloro-4-tri-                                                                  0.56    0    0   0   0                                     0.14  fluoromethyl-5-thiazole-                                                                     0.56   40   97  95   99                                    0.56  carboxylate   0.56   58   98  98   99                                    2.24                0.56   95   99  99  100                                    --    2'-Chloroethyl 2-chloro-4-                                                                   0.14    0    0   0   0                                     0.14  trifluoromethyl-5-thiazole-                                                                  0.14   50   98  98   99                                    0.56  carboxylate   0.14   75   99  99  100                                    2.24                0.14   88   99  99  100                                    --    2'-Chloroethyl 2-chloro-4-                                                                   0.56    0    0   0   0                                     0.14  trifluoromethyl-5-thiazole-                                                                  0.56   13   98  98   99                                    0.56  carboxylate   0.56   58   98  99   99                                    2.24                0.56   75   100 100 100                                    __________________________________________________________________________

                                      Table VIII                                   __________________________________________________________________________     Rate of             Rate of                                                                               Percent Inhibition                                  Herbicide           Safening    Green                                                                              Crab-                                                                              Barnyard                               (kg/h)                                                                               Safening Agent                                                                               Agent (kg/h)                                                                          Sorghum                                                                             Foxtail                                                                            grass                                                                              Grass                                  __________________________________________________________________________     1.12  --            --     70   100  99  99                                    2.24                       83   100 100  99                                    4.48                       97   100 100 100                                    --    Ethyl 2-phenoxy-4-trifluoro-                                                                 8.96    0    0   0   0                                     1.12  methyl-5-thiazolecarboxylate                                                                 8.96    5   100  99 100                                    2.24                8.96    8   100 100 100                                    4.48                8.96   35   100 100 100                                    --    2-Chloro-4-trifluoromethyl-                                                                  8.96   10    0   0   0                                     1.12  5-thiazolecarboxylic acid                                                                    8.96   40   100 100 100                                    2.24                8.96   60   100 100 100                                    4.48                8.96   65   100 100 100                                    --    Ethyl 2-chloro-4-pentafluoro-                                                                8.96    0    0   0   0                                     1.12  ethyl-5-thiazolecarboxylate                                                                  8.96   10   100  99  99                                    2.24                8.96   50   100 100 100                                    4.48                8.96   65   100 100 100                                    --    Ethyl 2-bromo-4-trifluoro-                                                                   8.96    0    0   0   0                                     1.12  methyl-5-thiazolecarboxylate                                                                 8.96    5   100 100 100                                    2.24                8.96   13   100 100 100                                    4.48                8.96   38   100 100 100                                    --    Ethyl 2-ethoxy-4-trifluoro-                                                                  8.96    0    0   0   0                                     1.12  methyl-5-thiazolecarboxylate                                                                 8.96   15   100 100  99                                    2.24                8.96   33   100 100 100                                    4.48                8.96   40   100 100 100                                    --    Ethyl 2-chloro-4-trichloro-                                                                  8.96    0    0   0   0                                     1.12  methyl-5-thiazolecarboxylate                                                                 8.96   25   100  99  99                                    2.24                8.96   60   100 100 100                                    4.48                8.96   80   100 100 100                                    --    N,N-diethyl-2-chloro-4-tri-                                                                  8.96    0    0   0   0                                     1.12  fluoromethyl-5-thiazole-                                                                     8.96   80   100 100 100                                    2.24  carboxamide   8.96   98   100 100 100                                    4.48                8.96   98   100 100 100                                    --    Triethanolamine salt of 2-                                                                   8.96    5   100  99  99                                    1.12  chloro-4-trifluoromethyl-5-                                                                  8.96   68   100 100 100                                    2.24  thiazolecarboxylic acid                                                                      8.96   94   100 100 100                                    4.48                8.96   100  100 100 100                                    __________________________________________________________________________

                                      Table IX                                     __________________________________________________________________________                             Percent Inhibition                                     Rate of         Rate of        Barn-                                           Herbicide       Safening       yard                                                                               Crab-    Green                              (kg/h)                                                                               Safening Agent                                                                           Agent (kg/h)                                                                          Rice                                                                              Sorghum                                                                             Grass                                                                              grass                                                                              Panicum                                                                             Foxtail                            __________________________________________________________________________     1.12  --        --     78 58   100  99 100   99                                2.24                   85 99   100 100 100  100                                4.48                   97 99   100 100 100  100                                --    Ethyl 2-chloro-4-                                                                        8.96    0  0    0   0   0    0                                 1.12  methyl-5-thiazole-                                                                       8.96   78 30   100 100 100  100                                2.24  carboxylate                                                                              8.96   73 28   100 100 100  100                                4.48            8.96   90 55   100 100 100  100                                --    Ethyl 2-chloro-4-                                                                        8.96    0  0    0   0   0    0                                 1.12  trifluoromethyl-5-                                                                       8.96   73  3   100 100  99   99                                2.24  thiazolecarboxylate                                                                      8.96   78 23   100 100 100  100                                4.48            8.96   85 30   100 100 100  100                                --    Ethyl 2-chloro-4-                                                                        8.96    0  0    0   0   0    0                                 1.12  ethyl-5-thiazole-                                                                        8.96   60 30   100  99 100   99                                2.24  carboxylate                                                                              8.96   85 75   100 100 100  100                                4.48            8.96   88 73   100 100 100  100                                __________________________________________________________________________

EXAMPLE 4

The procedure of Example 3 is repeated wherein the herbicide used is butachlor. Table X summarizes results obtained in accordance with this procedure.

                                      Table X                                      __________________________________________________________________________                            Percent Inhibition                                      Rate of         Rate of        Barn-                                           Herbicide       Safening       yard                                                                               Crab-    Green                              (kg/h)                                                                               Safening Agent                                                                           Agent (kg/h)                                                                          Rice                                                                              Sorghum                                                                             Grass                                                                              grass                                                                              Panicum                                                                             Foxtail                            __________________________________________________________________________     2.24  --        --     50 50   100 100  99  100                                4.48                   78 60   100 100 100  100                                8.96                   93 88   100 100 100  100                                2.24  Ethyl 2-chloro-4-                                                                        8.96   33  8   100 100 100  100                                4.48  methyl-5-thiazole-                                                                       8.96   53 18   100 100 100  100                                8.96  carboxylate                                                                              8.96   80 28   100 100 100  100                                2.24  Ethyl 2-chloro-4-                                                                        8.96   20  0   100 100 100  100                                4.48  trifluoromethyl-5-                                                                       8.96   55 20   100 100 100  100                                8.96  thiazolecarboxylate                                                                      8.96   68 13   100 100 100  100                                2.24  Ethyl 2-chloro-4-                                                                        8.96   20 13   100 100 100  100                                4.48  ethyl-5-thiazole-                                                                        8.96   20 15   100 100 100  100                                8.96  carboxylate                                                                              8.96   53 20   100 100 100  100                                __________________________________________________________________________

EXAMPLE 5

5.08 cm. of a good grade of top soil is placed in a 7.62 cm. deep plastic pot. A predetermined number of barnyard grass seeds are applied to the soil surface. A measured quantity of the safening agent dispersed or dissolved in a suitable carrier is sprayed on the soil surface. A measured quantity of butachlor herbicide dissolved in a solvent is sprayed on the soil surface. Pre-soaked rice is seeded into the pots that were previously flooded with water. The pots are flooded just above the soil surface for the duration of the test. The plants are observed at the end of approximately 21 days and the results in terms of percent inhibition recorded. For each test, a pot is prepared containing soil treated only with butachlor. For each test, pots are prepared containing soil treated only with the safening agent. Tables XI, XII and XIII represent the results of three separate tests conducted in accordance with the procedure of Example 5.

                  Table XI                                                         ______________________________________                                                                          Percent                                       Rate of                          Inhibition                                    Herb-                 Rate of         Barn-                                    icide                 Safening        yard                                     (kg/h)                                                                               Safening Agent  Agent (kg/h)                                                                              Rice Grass                                    ______________________________________                                         0.07  --              --         31   99                                       0.28                             74   100                                      1.12                             98   100                                      --    Phenyl 2-chloro-4-tri-                                                                         0.07        0    0                                       0.07  fluoromethyl-5-thiazole-                                                                       0.07        0   97                                       0.28  carboxylate     0.07       38   99                                       1.12                  0.07       90   100                                      --    Phenyl 2-chloro-4-tri-                                                                         0.28        0    0                                       0.07  fluoromethyl-5-thiazole-                                                                       0.28        8   98                                       0.28  carboxylate     0.28       25   99                                       1.12                  0.28       68   100                                      --    Phenyl 2-chloro-4-tri-                                                                         1.12        0    0                                       0.07  fluoromethyl-5-thiazole-                                                                       1.12        0   92                                       0.28  carboxylate     1.12       23   100                                      1.12                  1.12       63   100                                      --    Methyl 2chloro-4-tri-                                                                          0.07        0    0                                       0.07  fluoromethyl-5-thiazole-                                                                       0.07        5   95                                       0.28  carboxylate     0.07       68   99                                       1.12                  0.07       95   100                                      --    Methyl 2-chloro-4-tri-                                                                         0.28        0    0                                       0.07  fluoromethyl-5-thiazole-                                                                       0.28        0   98                                       0.28  carboxylate     0.28       35   99                                       1.12                  0.28       68   100                                      --    Methyl 2-chloro-4-tri-                                                                         1.12        0    0                                       0.07  fluoromethyl-5-thiazole-                                                                       1.12        0   97                                       0.28  carboxylate     1.12       20   99                                       1.12                  1.12       55   100                                      ______________________________________                                    

                  Table XII                                                        ______________________________________                                                                          Percent                                       Rate of                          Inhibition                                    Herb-                 Rate of         Barn-                                    icide                 Safening        yard                                     (Kg/h)                                                                               Safening Agent  Agent (kg/h)                                                                              Rice Grass                                    ______________________________________                                         0.07  --              --         56   91                                       0.28                             94   99                                       1.12                             100  100                                      --    Octyl 2-chloro-4-tri-                                                                          0.07        0    0                                       0.07  fluoromethyl-5-thiazole-                                                                       0.07       40   85                                       0.28  carboxylate     0.07       73   99                                       1.12                  0.07       99   100                                      --    Octyl 2-chloro-4-tri-                                                                          0.28        0    0                                       0.07  fluoromethyl-5-thiazole-                                                                       0.28        5   90                                       0.28  carboxylate     0.28       73   99                                       1.12                  0.28       97   100                                      --    Octyl 2-chloro-4-tri-                                                                          1.12        0    0                                       0.07  fluoromethyl-5-thiazole-                                                                       1.12       15   97                                       0.28  carboxylate     1.12       70   99                                       1.12                  1.12       99   100                                      --    Butoxyethyl 2-chloro-4-                                                                        0.07        0    0                                       0.07  trifluoromethyl-5-thia-                                                                        0.07       43   92                                       0.28  zolecarboxylate 0.07       83   99                                       1.12                  0.07       100  100                                      --    Butoxyethyl 2-chloro-4-                                                                        0.28        0    0                                       0.07  trifluoromethyl-5-thia-                                                                        0.28       18   93                                       0.28  zolecarboxylate 0.28       48   99                                       1.12                  0.28       95   100                                      --    Butoxyethyl 2-chloro-4-                                                                        1.12        0    0                                       0.07  trifluoromethyl-5-thia-                                                                        1.12        0   90                                       0.28  zolecarboxylate 1.12       48   99                                       1.12                  1.12       97   100                                      chloroethyl 2-chloro-                                                                0.07             0          0                                            0.07  4-trifluoromethyl-5-                                                                           0.07       30   95                                       0.28  thiazolecarboxylate                                                                            0.07       53   99                                       1.12                  0.07       98   100                                      chloroethyl 2-chloro-                                                                0.28             0          0                                            0.07  4-trifluoromethyl-5-                                                                           0.28        5   93                                       0.28  thiazolecarboxylate                                                                            0.28       48   99                                       1.12                  0.28       98   100                                      chloroethyl 2-chloro-                                                                1.12             0          0                                            0.07  4-trifluoromethyl-5-                                                                           1.12        0   83                                       0.28  thiazolecarboxylate                                                                            1.12       20   99                                       1.12                  1.12       85   100                                      ______________________________________                                    

                  Table XIII                                                       ______________________________________                                                                          Percent                                       Rate of               Rate of    Inhibition*                                   Herbicide             Safening        Barnyard                                 (kg/h)  Safening Agent                                                                               Agent (kg/h)                                                                              Rice Grass                                    ______________________________________                                         0.07    --            --          65   95                                      0.28                              93  100                                      1.12                             100  100                                      --      Methyl 2-chloro-4-                                                                           0.56        0    0                                       0.07    heptafluoropropyl-5-                                                                         0.56        55   99                                      0.28    thiazolecarboxylate                                                                          0.56       100  100                                      1.12                  0.56       100  100                                      ______________________________________                                          *Mean of two replicates                                                  

EXAMPLE 6

A good grade of top soil is placed in a container and compacted to a depth of approximately 1.27 cm. from the top of said container. A predetermined number of sorghum, green foxtail, crabgrass and barnyard grass were applied to the soil surface. The seeds were then covered with top soil and the surface was treated with a mixture of the herbicide and safening agent. The plants are observed at the end of approximately 18 days and the results in terms of percent inhibition recorded. Table XIV summarizes the results of tests conducted in accordance with Example 6.

                                      Table XIV                                    __________________________________________________________________________            Rate of         Rate of                                                                               Percent Inhibition                                      Herbicide       Safening    Green                                                                              Crab-                                                                              Barnyard                            Herbicide                                                                             (kg/h)                                                                               Safening Agent                                                                           Agent (kg/h)                                                                          Sorghum                                                                             Foxtail                                                                            grass                                                                              Grass                               __________________________________________________________________________     Alachlor                                                                              0.14  --        --     10   99  95  100                                 Alachlor                                                                              0.56  --        --     80   99  99  100                                 Alachlor                                                                              2.24  --        --     85   100 100 100                                   --   --    Ethyl 2-chloro-4-tri-                                                                    0.14    0    0   0   0                                               fluoromethyl-5-thia-                                                --   --    zolecarboxylate                                                                          0.56    5    0   0   0                                  ;10  --                                                                               --    Ethyl 2-chloro-4-tri-                                                                    2.24   15    0   0   0                                               fluoromethyl-5-thia-                                                           zolecarboxylate                                                   Alachlor                                                                              0.14  Ethyl 2-chloro-4-tri-                                                                    0.14    0   99  99  99                                               fluoromethyl-5-thia-                                              Alachlor                                                                              0.56  zolecarboxylate                                                                          0.14   20   99  99  100                                 Alachlor                                                                              2.24  Ethyl 2-chloro-4-tri-                                                                    0.14   55   100 100 100                                              fluoromethyl-5-thia-                                                           zolecarboxylate                                                   Alachlor                                                                              0.14  Ethyl 2-chloro-4-tri-                                                                    0.56    0   98  99  99                                               fluoromethyl-5-thia-                                              Alachlor                                                                              0.56  zolecarboxylate                                                                          0.56    5   99  99  99                                  Alachlor                                                                              2.24  Ethyl 2-chloro-4-tri-                                                                    0.56   55   100 100 99                                               fluoromethyl-5-thia-                                                           zolecarboxylate                                                   Alachlor                                                                              0.14  Ethyl 2-chloro-4-tri-                                                                    2.24   25   97  98  99                                               fluoromethyl-5-thia-                                              Alachlor                                                                              0.56  zolecarboxylate                                                                          2.24   13   100 99  99                                  Alachlor                                                                              2.24  Ethyl 2-chloro-4-tri-                                                                    2.24   38   100 100                                                  fluoromethyl-5-thia-                                                           zolecarboxylate                                                   2-Chloro-N-                                                                           0.14  --        --     13   97  97  98                                  (2-methoxy-                                                                    1-methyl-                                                                             0.56  --        --     60   98  99  99                                  ethyl)-6'-                                                                     ethyl-o-ace-                                                                          2.24  --        --     84   99  100 100                                 totoluidide                                                                    2-Chloro-N-                                                                           0.14  Ethyl 2-chloro-4-tri-                                                                    0.14    0   98  98  98                                  (2-methoxy-  fluoromethyl-5-thia-                                              1-methyl-                                                                             0.56  zolecarboxylate                                                                          0.14    0   99  99  99                                  ethyl)-6'-                                                                     ethyl-o-ace-                                                                          2.24  Ethyl 2-chloro-4-tri-                                                                    0.14   70   100 100 100                                 totoluidide  fluoromethyl-5-thia-                                                           zolecarboxylate                                                   2-Chloro-N-                                                                           0.14  Ethyl 2-chloro-4-tri-                                                                    0.56    8   98  97  98                                  (2-methoxy-  fluoromethyl-5-thia-                                              1-methyl-                                                                             0.56  zolecarboxylate                                                                          0.56   10   99  99  99                                  ethyl)-6'-                                                                     ethyl-o-ace-                                                                          2.24  Ethyl 2-chloro-4-tri-                                                                    0.56   15   100 100 100                                 totoluidide  fluoromethyl-5-thia-                                                           zolecarboxylate                                                   2-Chloro-N-                                                                           0.14  Ethyl 2-chloro-4-tri                                                                     2.24   10   98  98  00                                  (2-methoxy-  fluoromethyl-5-thia-                                              1-methyl-                                                                             0.56  zolecarboxylate                                                                          2.24   10   100 99  100                                 ethyl)-6'-                                                                     ethyl-o-ace-                                                                          2.24  Ethyl 2-chloro-4-tri-                                                                    2.24   15   100 100 100                                 totoluidide  fluoromethyl-5-thia-                                                           zolecarboxylate                                                   __________________________________________________________________________

EXAMPLE 7

A predetermined number of corn, sorghum and rice seeds were placed on top of a good grade of top soil. The over layer was then treated with an appropriate amount of safening agent. A cover layer of soil treated with the appropriate herbicide was placed on top of the seeds. The plants were observed at the end of approximately 21 days and the results in terms of percent inhibition recorded. Table XV summarizes the results of tests conducted in accordance with Example 7.

                                      Table XV                                     __________________________________________________________________________            Rate of           Rate of                                                      Herbicide         Safening                                                                              Percent Inhibition                             Herbicide                                                                             (kg/h)                                                                               Safening Agent                                                                             Agent (kg/h)                                                                          Sorghum                                                                             Rice                                                                              Corn                                   __________________________________________________________________________     Alachlor                                                                              0.56  --          --     88   98 0                                      Alachlor                                                                              4.48  --          --     99   100                                                                               25                                      --    --    Ethyl 2-chloro-4-tri-                                                                      8.96   0     0 0                                                   fluoromethyl-5-thiazole-                                                       carboxylate                                                       Alachlor                                                                              0.56  Ethyl 2-chloro-4-tri-                                                                      8.96   5    83 0                                                   fluoromethyl-5-thiazole-                                                       carboxylate                                                       Alachlor                                                                              4.48  Ethyl 2-chloro-4-tri-                                                                      8.96   58   100                                                                               30                                                  fluoromethyl-5-thiazole-                                                       carboxylate                                                       Butachlor                                                                             1.12  --          --     30   20 0                                      Butachlor                                                                             8.96  --          --     85   95 20                                     Butachlor                                                                             1.12  Ethyl 2-chloro-4-tri-                                                                      8.96   0     0 0                                                   fluoromethyl-5-thiazole-                                                       carboxylate                                                       Butachlor                                                                             8.96  Ethyl 2-chloro- 4-tri-                                                                     8.96   25   38 33                                                  fluoromethyl-5-thiazole-                                                       carboxylate                                                       2-Chloro-N-                                                                           0.56  --          --     50   73 8                                      (2-methoxy-                                                                    1-methyl-                                                                             4.48  --          --     97   100                                                                               43                                     ethyl)-6'-                                                                     ethyl-o-ace-                                                                          0.56  Ethyl 2-chloro-4-tri-                                                                      8.96   0    55 10                                     Totoluide    fluoromethyl-5-thiazole-                                          totoluide                                                                             4.48  carboxylate 8.96   75   100                                                                               10                                     __________________________________________________________________________

As noted above, crop plants may be protected from herbicidal activity by treating the crop seed with the safening agent prior to planting. Example 8 illustrates such activity.

EXAMPLE 8

Sorghum seeds were treated with a solution of the appropriate safeing agent in dichloromethane. The solvent was evaporated which left only the safening agent on the seed. Untreated and treated sorghum seeds were planted in pots. Selected weed species were planted in separate pots. 1.27 cm. deep soil cover layer was placed on the pre-seeded pots. The soil surface was then treated with the herbicide. Approximately 21 days later, the results were observed and recorded. Table XVI summarizes the results observed when tests were conducted in accordance with Example 8.

                                      Table XVI                                    __________________________________________________________________________                              Percent Sorghum Inhibition                                   Rate of           Seed Treatment Concentration (grams                          Herbicide         of safening agent/kilograms of seed)                  Herbicide                                                                             (kg/h)                                                                              Safening Agent                                                                              0   0.6  2.5  10                                      __________________________________________________________________________     Alachlor                                                                              --   Ethyl 2-chloro-4-tri-                                                                       0   0    0    15                                                  fluoromethyl-5-thia-                                               Alachlor                                                                              0.14 zolecarboxylate                                                                             83  0    0    13                                                  Ethyl 2-chloro-4-tri-                                              Alachlor                                                                              0.56 fluoromethyl-5-thia                                                                         96  0    0    25                                                  zolecarboxylate                                                                Ethyl 2-chloro-4-tri-                                              Alachlor                                                                              2.24 fluoromethyl-5-thia-                                                                        98  18   13   35                                                  zolecarboxylate                                                    Alachlor                                                                              --   Ethyl 2-chloro-4-t-                                                                         0   0    5    25                                                  butyl-5-thiazole-                                                  Alachlor                                                                              0.14 carboxylate  23  3    0    10                                                  Ethyl 2-chloro-4-t-                                                Alachlor                                                                              0.56 butyl-5-thiazole-                                                                           65  0    0    0                                                   carboxylate                                                                    Ethyl 2-chloro-4-t-                                                Alachlor                                                                              2.24 butyl-5-thiazole-                                                                           80  30   28   28                                                  carboxylate                                                        2-Chloro-N-                                                                           --   Ethyl 2-chloro-4-tri-                                                                       0   0    0    20                                      (2-methoxy- fluoromethyl-5-thia-                                               1-methyl-                                                                             0.07 zolecarboxylate                                                                             0   0    0    23                                      ethyl)-6'-  Ethyl 2-chloro-4-tri-                                              ethyl-o-ace-                                                                          0.14 fluoromethyl-5-thia-                                                                        5   0    0    15                                      totoluidide zolecarboxylate                                                    2-Chloro-N-                                                                    (2-methoxy- Ethyl 2-chloro-4-tri-                                              1-methyl-   fluoromethyl-5-thia                                                ethyl)-6'-                                                                            0.28 zolecarboxylate                                                                             0   0    0    45                                      ethyl-o-ace-                                                                   totoluidide                                                                    2-Chloro-N-                                                                    (2-methoxy- Ethyl 2-chloro-4-tri-                                              1-methyl-   fluoromethyl-5-thia                                                ethyl)-6'-                                                                            0.56 zolecarboxylate                                                                             25  0    0    25                                      ethyl-o-ace                                                                    totoluidide                                                                    2-Chloro-N-                                                                    (2-methoxy- Ethyl 2-chloro-4-tri-                                              1-methyl-   fluoromethyl-5-thia                                                ethyl)-6'-                                                                            1.12 zolecarboxylate                                                                             40  5    0    35                                      ethyl-o-ace                                                                    totoluidide                                                                    2-Chloro-N-                                                                    (2-methoxy- Ethyl-2-chloro-4-tri-                                              1-methyl-   fluoromethyl-5-thia                                                ethyl)-6'-                                                                            2.24 zolecarboxylate                                                                             73  15   13   23                                      ethyl-o-ace                                                                    totoluidide                                                                    Alachlor                                                                              --   Butyl 2-chloro-4-tri-                                                                       0   0    0    10                                                  fluoromethyl-5-thia-                                               Alachlor                                                                              0.28 zolecarboxylate                                                                             83  0    5    13                                                  Butyl 2-chloro-4-tri-                                              Alachlor                                                                              1.12 fluoromethyl-5-thia-                                                                        96  5    8    15                                                  zolecarboxylate                                                                Butyl 2-chloro-4-tri-                                              Alachlor                                                                              4.48 fluoromethyl-5-thia-                                                                        98  13   8    18                                                  zolecarboxylate                                                    Alachlor                                                                              --   Hexyl 2-chloro-4-tri-                                                                       0   0    5    18                                                  fluoromethyl-5-thia-                                               Alachlor                                                                              0.28 zolecarboxylate                                                                             83  8    13   30                                                  Hexyl 2-chloro-4-tri-                                              Alachlor                                                                              1.12 fluoromethyl-5-thia-                                                                        96  8    13   33                                                  zolecarboxylate                                                                Hexyl 2-chloro-4-tri-                                              Alachlor                                                                              4.48 fluoromethyl-5-thia-                                                                        98  13   15   35                                                  zolecarboxylate                                                    Alachlor                                                                              --   Octyl 2-chloro-4-tri-                                                                       0   0    0    13                                                  fluoromethyl-5-thia-                                               Alachlor                                                                              0.28 zolecarboxylate                                                                             83  10   10   13                                                  Octyl 2-chloro-4-tri-                                              Alachlor                                                                              1.12 fluoromethyl-5-thia-                                                                        96  8    5    10                                                  zolecarboxylate                                                                Octyl 2-chloro-4-tri-                                              Alachlor                                                                              4.48 fluoromethyl-5-thia-                                                                        98  25   23   23                                                  zolecarboxylate                                                    Alachlor                                                                              --   Phenyl 2-chloro-4-tri-                                                                      0   0    0    10                                                  fluoromethyl-5-thia-                                               Alachlor                                                                              0.28 zolecarboxylate                                                                             83  10   10   18                                                  Phenyl 2-chloro-4-tri-                                             Alachlor                                                                              1.12 fluoromethyl-5-thia-                                                                        96  5    5    20                                                  zolecarboxylate                                                                Phenyl 2-chloro-4-tri-                                             Alachlor                                                                              4.48 fluoromethyl-5-thia-                                                                        98  13   15   35                                                  zolecarboxylate                                                    Alachlor                                                                              --   Ethyl 2-phenoxy-4-tri-                                                                      0   0    0    5                                                   fluoromethyl-5-thia-                                               Alachlor                                                                              0.28 zolecarboxylate                                                                             83  0    0    5                                                   Ethyl 2-phenoxy-4-tri-                                             Alachlor                                                                              1.12 fluoromethyl-5-thia-                                                                        96  33   30   23                                                  zolecarboxylate                                                                Ethyl 2-phenoxy-4-tri-                                             Alachlor                                                                              4.48 fluoromethyl-5-thia-                                                                        98  88   88   90                                                  zolecarboxylate                                                    Alachlor                                                                              --   Allyl 2-chloro-4-tri-                                                                       0   0    0    --                                                  fluoromethyl-5-thia-                                               Alachlor                                                                              0.28 zolecarboxylate                                                                             83  0    5    --                                                  Allyl 2-chloro-4-tri-                                              Alachlor                                                                              1.12 fluoromethyl-5-thia-                                                                        96  13   10   --                                                  zolecarboxylate                                                                Allyl 2-chloro-4-tri-                                              Alachlor                                                                              4.48 fluoromethyl-5-thia-                                                                        98  23   20   --                                                  zolecarboxylate                                                    Alachlor                                                                              --   2-Chloro-4-trifluoro-                                                                       0   0    10   20                                                  methyl-5-thiazole-                                                 Alachlor                                                                              0.28 carboxylic acid                                                                             83  10   13   35                                                  2-Chloro-4-trifluoro-                                              Alachlor                                                                              1.12 methyl-5-thiazole-                                                                          96  10   10   38                                                  carboxylic acid                                                                2-Chloro-4-trifluoro-                                              Alachlor                                                                              4.48 methyl-5-thiazole-                                                                          98  18   18   40                                                  carboxylic acid                                                    Alachlor                                                                              --   Isopropyl 2-chloro-4-                                                                       0   0    5    30                                                  trifluoromethyl-5-thia-                                            Alachlor                                                                              0.28 zolecarboxylate                                                                             83  0    0    20                                                  Isopropyl 2-chloro-4-                                              Alachlor                                                                              1.12 trifluoromethyl-5-thia-                                                                     96  0    10   30                                                  zolecarboxylate                                                                Isopropyl 2-chloro-4-                                              Alachlor                                                                              4.48 trifluoromethyl-5-thia-                                                                     98  23   28   58                                                  zolecarboxylate                                                    Alachlor                                                                              --   β-trichloroethyl 2-                                                                    0   0    5    13                                                  chloro-4-trifluoromethyl-                                          Alachlor                                                                              0.28 5-thiazolecarboxylate                                                                       93  10   13   30                                                  β-trichloroethyl 2-                                           Alachlor                                                                              1.12 chloro-4-trifluoromethyl                                                                    93  5    13   23                                                  5-thiazolecarboxylate                                                          β-trichloroethyl 2-                                           Alachlor                                                                              4.48 chloro-4-trifluoromethyl-                                                                   96  20   20   23                                                  5-thiazolecarboxylate                                              Alachlor                                                                              --   Methyl 2-chloro-4-tri-                                                                      0   0    13   22                                                  fluoromethyl-5-thia-                                               Alachlor                                                                              0.28 zolecarboxylate                                                                             85  0    15   23                                                  Methyl 2-chloro-4-tri                                              Alachlor                                                                              1.12 fluoromethyl-5-thia-                                                                        98  55   40   50                                                  zolecarboxylate                                                                Methyl 2-chloro-4-tri-                                             Alachlor                                                                              4.48 fluoromethyl-5-thia-                                                                        98  83   65   63                                                  zolecarboxylate                                                    Alachlor                                                                              --   Benzyl 2-chloro-4-tri-                                                                      0   0    13   20                                                  fluoromethyl-5-thiazole-                                           Alachlor                                                                              0.28 carboxylate  85  0    15   23                                                  Benzyl 2-chloro-4-tri-                                             Alachlor                                                                              1.12 fluoromethyl-5-thiazole-                                                                    98  30   35   45                                                  carboxylate                                                                    Benzyl 2-chloro-4-tri-                                             Alachlor                                                                              4.48 fluoromethyl-5-thiazole-                                                                    98  80   65   63                                                  carboxylate                                                        Alachlor                                                                              --   Butoxyethyl 2-chloro-4-                                                                     0   0    10   20                                                  trifluoromethyl-5-thia-                                            Alachlor                                                                              0.28 zolecarboxylate                                                                             85  0    10   23                                                  Butoxyethyl 2-chloro-4-                                            Alachlor                                                                              1.12 trifluoromethyl-5-thia-                                                                     97  55   45   63                                                  zolecarboxylate                                                                Butoxyethyl 2-chloro-4-                                            Alachlor                                                                              4.48 trifluoromethyl-5-thia-                                                                     98  78   63   63                                                  zolecarboxylate                                                    Alachlor                                                                              --   β-chloroethyl 2-chloro-                                                                0   0    18   48                                                  4-trifluoromethyl-5-                                               Alachlor                                                                              0.28 thiazolecarboxylate                                                                         85  10   23   50                                                  β-chloroethyl 2-chloro-                                       Alachlor                                                                              1.12 4-trifluoromethyl-5-                                                                        98  30   40   65                                                  thiazolecarboxylate                                                            β-chloroethyl 2-chloro                                        Alachlor                                                                              4.48 4-trifluoromethyl-5-                                                                        98  75   65   70                                                  thiazolecarboxylate                                                Alachlor                                                                              --   Ethyl 2-bromo-4-tri-                                                                        0   0    15   30                                                  fluoromethyl-5-thia-                                               Alachlor                                                                              0.28 zolecarboxylate                                                                             85  18   28   55                                                  Ethyl 2-bromo-4-tri-                                               Alachlor                                                                              1.12 fluoromethyl-5-thia-                                                                        98  40   43   68                                                  zolecarboxylate                                                                Ethyl 2-bromo-4-tri-                                               Alachlor                                                                              4.48 fluoromethyl-5-thia-                                                                        98  75   65   68                                                  zolecarboxylate                                                    Alachlor                                                                              --   Ethyl 2-iodo-4-tri-                                                                         0   0    15   60                                                  fluoromethyl-5-thia-                                               Alachlor                                                                              0.28 zolecarboxylate                                                                             85  20   30   73                                                  Ethyl 2-iodo-4-tri-                                                Alachlor                                                                              1.12 fluoromethyl-5-thia-                                                                        98  45   45   80                                                  zolecarboxylate                                                    Alachlor                                                                              4.48 Ethyl 2-iodo-4-tri-                                                                         98  80   63   85                                                  fluoromethyl-6-thio-                                                           zolecarboxylate                                                    Alachlor                                                                              --   p-Chlorophenyl 2-chloro-                                                                    0   0    0    0                                                   4-trifluoromethyl-5-                                               Alachlor                                                                              0.28 thiazolecarboxylate                                                                         60  0    0    5                                                   p-Chlorophenyl 2-chloro-                                           Alachlor                                                                              1.12 4-trifluoromethyl-5-                                                                        90  15   10   13                                                  thiazolecarboxylate                                                            p-Chlorophenyl 2-chloro-                                           Alachlor                                                                              4.48 4-trifluoromethyl-5-                                                                        99  78   45   25                                                  thiazolecarboxylate                                                Alachlor                                                                              --   Butoxyethyl 2-chloro-                                                                       0   0    0    5                                                   4-trifluoromethyl-5-                                               Alachlor                                                                              0.28 thiazolecarboxylate                                                                         83  10   10   18                                                  Butoxyethyl 2-chloro-                                              Alachlor                                                                              1.12 4-trifluoromethyl-5-                                                                        93  48   40   50                                                  thiazolecarboxylate                                                            Butoxyethyl 2-chloro-                                              Alachlor                                                                              4.48 4-trifluoromethyl-5-                                                                        99  70   60   45                                                  Thiazolecarboxylate                                                __________________________________________________________________________

As noted, selected weed species were planted as a control to determine the efficiency of the herbicide. At rates between 0.28 and 1.12 kilograms per hectare, weed inhibition ranged from 80 to 100 percent.

EXAMPLE 9

A good grade of top soil is placed in a container and compacted to a depth of approximately 1.27 cm. from the top of said container. A predetermined number of sorghum, rice, corn, barnyard grass and foxtail seeds are applied to the soil surface. The seeds are then covered with top soil that had been treated with the herbicide and safening agent by applying said herbicide and safening agent to the soil and incorporating the herbicide and safening agent therein. The plants are observed at the end of approximately 19 days and the results in terms of percent inhibition recorded. Table XVII summarizes the results of tests conducted in accordance with Example 9.

                                      Table XVII                                   __________________________________________________________________________                              Percent Inhibition                                            Rate                                                                               Safening Rate           Barnyard                                   Herbicide                                                                              (kg/h)                                                                             Agent    (kg/h)                                                                             Rice                                                                              Sorghum                                                                             Corn                                                                              Grass                                                                               Foxtail                               __________________________________________________________________________     N-(ethoxy-                                                                             0.28                                                                                 --     --  80 63   35 99   99                                    methyl)-N-                                                                     (2-ethyl-                                                                              2.24             100                                                                               98   94 100  100                                   6-methyl-                                                                      1-cyclo-                                                                       hexen-1-yl)-                                                                   2-chloroacet-                                                                  amide                                                                          N-(ethoxy-                                                                             0.28                                                                               Ethyl 2-chloro-4-                                                                       8.96                                                                               65 8    0  99   99                                    methyl)-N-  trifluoromethyl-                                                   (2-ethyl-                                                                              2.24                                                                               5-thiazolecar-                                                                          8.96                                                                               98 53   20 100  100                                   6-methyl-   boxylate                                                           1-cyclo-                                                                       hexen-1-yl)-                                                                   2-chloroacet-                                                                  amide                                                                          N-(ethoxy-                                                                             0.28                                                                                 --     --  35 18   10 99   99                                    methyl)-N-                                                                     (2,5-dimethyl-                                                                         2.24                                                                                 --     --  98 40   35 100  100                                   1-cyclopenten-                                                                 1-yl)-2-chloro-                                                                acetamide                                                                      N-(ethoxy-                                                                             0.28                                                                               Ethyl 2-chloro-4-                                                                       8.96                                                                               30 0    0  99   99                                    methyl)-N-  trifluoromethyl-                                                   (2,5-dimethyl-                                                                         2.24                                                                               5-thiazolecar-                                                                          8.96                                                                               85 15   10 99   99                                    1-cyclopenten-                                                                             boxylate                                                           1-yl)-2-chloro-                                                                acetamide                                                                      __________________________________________________________________________

EXAMPLE 10

Two rows of each crop and weed were seeded at 1.86 to 3.1 cm. depth in Ray slit loam soil. The soil is then treated with the herbicide and safening agent. Approximately 19 days later, the plants were observed and the results recorded. Table XVIII summarizes the results of tests conducted in accordance with Example 10.

                                      Table XVIII                                  __________________________________________________________________________                            Percent Inhibition                                                                                Barn-                                       Rate                                                                               Safening                                                                               Rate   Sor-   Jimson                                                                             Morning                                                                             yard                                                                               Pani-                                                                             Fox-                          Herbicide                                                                             (kg/h)                                                                             Agent   (kg/h)                                                                             Corn                                                                              ghum                                                                               Rice                                                                              weed                                                                               Glory                                                                               Grass                                                                              cum                                                                               tail                          __________________________________________________________________________     Alachlor                                                                              4.48                                                                                 --    --  28 77  100                                                                               89  52   100 100                                                                               100                           Alachlor                                                                              4.48                                                                               Ethyl 2-                                                                               2.24                                                                               13 33  100                                                                               93  60   100 100                                                                               100                                      trifluoro-                                                                     methyl-5-thia-                                                                 zolecarboxylate                                                     2-Chloro-N-                                                                           4.48                                                                                 --    --  62 87  100                                                                               92  42   100 100                                                                               100                           (2-methoxy-                                                                    1-methyl-                                                                             4.48                                                                               Ethyl 2-                                                                               2.24                                                                               23 28  100                                                                               90  40   100 100                                                                               100                           ethyl)-6'- chloro-4-                                                           ethyl-o-   trifluoro-                                                          aceto-     methyl-5-thia-                                                      toluidide  zolecarboxylate                                                     2-Chloro-N-                                                                           3.36                                                                                 --    --  60 89  100                                                                               99  65   100 100                                                                               100                           (ethoxy-                                                                       methyl)-6'-                                                                           3.36                                                                               Ethyl 2-                                                                               2.24                                                                               32 63  100                                                                               99  70   100 100                                                                               100                           ethyl-o-   chloro-4-                                                           aceto-     trifluoro-                                                          toluidide  methyl-5-thia-                                                                 zolecarboxylate                                                     __________________________________________________________________________

The above examples illustrate that the thiazolecarboxylates of the present invention are useful in reducing herbicidal injury to crop plants, especially sorghum and rice. The safening agents may be applied to the plant locus as a mixture, i.e., a mixture of a herbicidally effective amount of acetamide herbicide and a safening effective amount of safening agent, or sequentially, i.e., the plant locus may be treated with an effective amount of the herbicide followed by a treatment with the safening agent or vice versa. The ratio of herbicide to safening agent may vary depending upon the crop to be protected, weeds to be inhibited, herbicide used, etc., but normally a herbicide to safening agent ratio ranging from 1:25 to 25:1 (preferably 1:5 to 5:1) parts by weight may be employed.

The herbicide, safening agent or mixture thereof may be applied to the plant locus alone or the herbicide, safening agent or mixture thereof may be applied in conjunction with a material referred to in the art as an adjuvant in liquid or solid form. Mixtures containing the appropriate herbicide and safening agent usually are prepared by admixing said herbicide and safening agent with an adjuvant including diluents, extenders, carriers and conditioning agents to provide compositions in the form of finely divided particulate solids, granules, pellets, wettable powders, dusts, solutions and aqueous dispersions or emulsions. Thus, the mixture may include an adjuvant such as a finely-divided particulate solid, a solvent liquid of organic origin, water, a wetting agent, dispersing agent, or emulsifying agent or any suitable combination of these.

When applying the herbicide, safening agent or mixture thereof to the plant locus, useful finely-divided solid carriers and extenders include, for example, the talcs, clays, pumice, silica, diatomaceous earth, quartz, Fullers earth, sulfur, powdered cork, powdered wood, walnut flour, chalk, tobacco dust, charcoal and the like. Typical liquid diluents useful include for example, Stoddard solvent, acetone, alcohols, glycols, ethyl acetate, benzene and the like. Such compositions, particularly liquids and wettable powders, usually contain as a conditioning agent one or more surface-active agents in amounts sufficient to render a given composition readily dispersible in water or in oil. By the term "surface-active agent", it is understood that wetting agents, dispersing agents, suspending agents and emulsifying agents are included therein. Such surface-active agents are well known and reference is made to U.S. Pat. No. 2,547,724, Columns 3 and 4, for detailed examples of the same.

Compositions of this invention generally contain from about 5 to 95 parts herbicide and safening agent, about 1 to 50 parts surface-active agent and about 4 to 94 parts solvent, all parts being by weight based on the total weight of the composition.

The application of the herbicide, safening agent or mixture thereof in a liquid or particulate solid form can be carried out by conventional techniques utilizing, for example, spreaders, power dusters, boom and hand sprayers, spray dusters and granular applications. The compositions can also be applied from airplanes as a dust or spray. If desired, application of the compositions of the invention to plants can be accomplished by incorporating the compositions in the soil or other media.

The above examples also illustrate that the crop may be protected by treating the crop seed with an effective amount of safening agent prior to planting. Generally, small amounts of safening agent are required to treat such seeds. Table XVI illustrates that a weight ratio of as little as 0.6 parts of safener per 1000 parts of seed may be effective. The amount of safener utilized in treating the seed may be increased if desired. Generally, however, a weight ratio of safening agent to seed weight may range from 0.1 to 10.0 parts of safening agent per 1000 parts of seed. The determination of the effective amount of safening agent required is well within the skill of the art.

Since only a very small amount of active safening agent is usually required for the seed treatment, the compound preferably is formulated as a powder or an emulsifiable concentrate which can be diluted with water by the seed treater for use in the seed treating apparatus. Of course, under certain conditions, it may be desirable to dissolve the safening agent in an organic solvent for use as a seed treatment or the pure compound alone may be used under properly controlled conditions.

There are thus also provided by this invention novel seed treating compositions containing one or more of the described active safening agents intimately dispersed in an inert carrier or diluent for the intended use. Such carriers may be either solids, such as talc, clay, diatomaceous earth, sawdust, calcium carbonate, and the like or liquids such as water, kerosene, acetone, benzene, toluene, xylene, and the like in which the active agent may be either dissolved or dispersed. Emulsifying agents are advisably used to achieve a suitable emulsion if two immiscible liquids are used as a carrier. Wetting agents may also be used to aid in dispersing the active safening agent in liquids used as a carrier in which the agent is not completely soluble. Emulsifying agents and wetting agents are sold under numerous tradenames and may be either pure compounds, mixtures of compounds of the same general groups, or they may be mixtures of compounds of different classes. Typical satisfactory surface-active agents which may be used are alkali metal higher alkylarylsulfonates such as sodium dodecylbenzenesulfonate and the sodium salts of alkylnaphthalenesulfonic acids, fatty alcohol sulfates such as the sodium salts of monoesters of sulfuric acid with n-aliphatic alcohols containing 8-18 carbon atoms, long chain quaternary ammonium compounds, sodium salts of petroleum-derived alkylsulfonic acids, polyethylene sorbitan monooleate, alkylaryl polyether alcohols, water-soluble lignin sulfonate salts, alkalicasein compositions, long chain alcohols usually containing 10-18 carbon atoms, and condensation products of ethylene oxide with fatty acids, alkylphenols and mercaptans.

PREPARATION OF THE SAFENING AGENTS

The 2,4-disubstituted-5-thiazolecarboxylic acids and derivatives of the foregoing formula may be prepared generally utilizing one of two procedures. The first method encompasses the preparation of 2-oxo-2,3-dihydro-4-substituted-5-thiazolecarboxylates by reacting portions of β-aminoacrylates and chlorocarbonylsulfenyl chloride. Crystallization of the resulting mixture from hexane yields the appropriate 2-oxo-2,3-dihydro-4-substituted-5-thiazolecarboxylate which may be converted to the appropriate 2-chloro-4-substituted-5-thiazolecarboxylate by reaction with excess phosphorus oxychloride. Excess phosphorus oxychloride is removed under reduced pressure and the residue poured into ice water. Extraction with ether and washing with 5% sodium hydroxide results in the 2-chloro-4-substituted-5-thiazolecarboxylate. For purposes of clarification, this method is summarized by the following scheme: ##STR2##

β-aminoacrylates may be prepared according to known procedures such as that specified in Lutz et al, Journal of Heterocyclic Chemistry, Volume 9, Page 513 (1972) or they may be prepared by mixing 0.5 moles of ethyl acetoacetate or methyl acetoacetate in 200 ml. of methanol and 100 ml. of saturated sodium acetate and passing through the appropriate nitrile (perfluorinated if R is to be perfluorinated) for several hours. The reaction mixture is poured into ice water and the organic layer extracted with ether. The ether solution is dried and concentrated and the residue is distilled. A mixture of about 0.1 mole of said residue and 50 ml. of 30% ammonium hydroxide or sodium hydroxide is stirred for a long period. The reaction mixture is extracted with methylene chloride and the methylene chloride extracts dried and concentrated. Fractional distillation of the residue results in the β-aminoacrylate.

In order to more fully illustrate the manner in which the 2,4-disubstituted-5-thiazolecarboxylates of the present invention are prepared, the following examples are presented.

EXAMPLE 11 Preparation of Ethyl 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylate.

A mixture of 13.0 g (0.0992 mole) of chlorocarbonylsulfenyl chloride, 17 g (0.0928 mole) of ethyl 3-amino-4,4,4-trifluorocrotonate and 50 ml. of chlorobenzene was heated at 135° C. for 2 hours, cooled and triturated with 200 ml. of petroleum ether. The light yellow precipitate was recrystallized from hexane-ether to give 12.2 g (55%) of white prisms, m.p. 121°-123° C., which was identified as ethyl 2,3-dihydro-2-oxo-4-trifluoromethyl-5-thiazolecarboxylate. A mixture of 10 g (0.0415 mole) of ethyl 2,3-dihydro-2-oxo-4-trifluoromethyl-5-thiazolecarboxylate, 30 ml. of POCl₃ and 1 ml. of dimethylformamide was held at reflux for 87 hours. The reaction mixture was poured into 500 ml. of ice water and extracted three times with 60 ml. of ether. The ether solution was washed with saturated sodium chloride solution, dried (MgSO₄) and concentrated under reduced pressure to give 10.2 g of light yellow solid, m.p. 57°-60° C., which was recrystallized from hexane to give 9.95 g (92.4%) of ethyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate as light yellow solid, m.p. 58°-59° C.

Anal. Calc'd. for C₇ H₅ F₃ ClNO₂ S: C, 32.38; H, 1.94; N, 5.40. Found: C, 32.33; H, 1.98; N, 5.35.

EXAMPLE 12 Preparation of Ethyl 2-Chloro-4-Pentafluoroethyl-5-Thiazolecarboxylate.

To a stirred mixture of 65 g (0.4995 ) mole of ethyl acetoacetate, 200 ml. of methanol and 100 ml. of saturated sodium acetate at 50° C. was introduced 100 g (0.769 mole) of pentafluoropropionitrile in 3 hours. The reaction mixture was poured into 1200 ml. of water. An oil separated from the reaction mixture. The aqueous solution was extracted with ether. The ether solution was combined with the oil, dried (MgSO₄) and concentrated under reduced pressure. The residue was distilled to give 40 g (37%) of ethyl 2-acetyl-3-amino-4,4,5,5,5-pentafluoro-2-pentenoate. A mixture of 21.8 g (0.0790 mole) of ethyl 2-acetyl-3-amino-4,4,5,5,5-pentafluoro-2-pentenoate and 75 ml. of 58% ammonium hydroxide was stirred for 66 hours. The reaction mixture was extracted with ether. The ether solution was dried (MgSO₄) and concentrated under reduced pressure. The residue was distilled to give 16.3 g (88%) of ethyl 3-amino-4,4,5,5,5-pentafluoro-2-pentenoate, n_(D) ²⁵ =1.4011. A well stirred mixture of 54 g (0.23 mole) of ethyl 3-amino-4,4,5,5,5-pentafluoro-2-pentenoate and 31 g (0.237 mole) of chlorocarbonylsulfenyl chloride was held at 100° C. for 1 hour. The reaction mixture was cooled and triturated with hexane. The solid precipitate was washed with water and recrystallized from hexane-ether to give 31 g (46%) of ethyl 2,3-dihydro-2-oxo-4-pentafluoroethyl-5-thiazolecarboxylate, m.p. 95°-97° C. A mixture of 10 g (0.0344 mole) of ethyl 2,3-dihydro-2-oxo-4-pentafluoroethyl-5-thiazole-carboxylate, 4 g (0.0506 mole) of pyridine and 150 ml. of phosphorus oxychloride was held at reflux for 18 hours. Excess phosphorus oxychloride was removed under reduced pressure. The residue was treated with water and extracted with ether. The ether solution was dried (MgSO₄) and concentrated under reduced pressure. The residue was distilled to give 7.5 g (71%) of ethyl 2-chloro-4-pentafluoroethyl-5-thiazolecarboxylate, n_(D) ²⁵ =1.4460.

Anal. Calc'd. for C₈ H₅ ClF₅ NO₂ S: C, 31.03; H, 1.63; N, 4.52. Found: C, 30.62; H, 1.18; N, 5.08.

EXAMPLE 13 Preparation of Methyl 2-Chloro-4-Heptafluoropropyl-5-Thiazolecarboxylate.

The procedure of Example 12 was repeated utilizing methyl acetoacetate in lieu of ethyl acetoacetate and heptafluorobutyronitrile in lieu of pentafluoropropionitrile to prepare 0.3 g of methyl 2-chloro-4-heptafluoropropyl-5-thiazolecarboxylate as a colorless liquid; n_(D) ²⁵ =1.4352.

Anal. Calc'd. for C₈ H₃ ClF₇ NO₂ S: C, 27.80; H, 0.87; N, 4.05. Found: C, 27.42; H, 0.87; N, 4.03.

EXAMPLE 14 Preparation of Ethyl 2-Chloro-4-Trichloromethyl-5-Thiazolecarboxylate.

To 130.14 g (1.00 mole) of ethyl acetoacetate was added 1.5 g of sodium. The reaction temperature increased spontaneously to 50° C. The reaction mixture was cooled with an ice bath. To the cooled reaction mixture was added, with vigorous stirring at 30°-50° C., 144.3 g (1.00 mole) of trichloroacetonitrile in 30 minutes. After complete addition of the trichloroacetonitrile, the reaction mixture was cooled with a dry ice bath. No precipitate of the ethyl 2-acetyl-3-amino-4,4,4-trichlorocrotonate formed. Part of the above product was stirred with 100 ml. of concentrated 28-30% ammonium hydroxide for 2 hours. The reaction mixture was then extracted with ether. The ether solution was dried (CaSO₄) and concentrated to give 180 g (82.5%) of crude ethyl 3-amino-4,4,4-trichlorocrotonate. Part of this crude material (20 g) was distilled at 0.5 mm Hg to give 11.7 g of pure product, m.p. 91°-95° C. To a cold (10° C.) solution of 21.8 g (0.0937 mole) of crude ethyl 3-amino-4,4,4-trichlorocrotonate in 15 ml. of chlorobenzene was added 13.5 g (0.103 mole) of chlorocarbonylsulfenyl chloride. The reaction temperature rose spontaneously to 35° C. after the ice water bath was removed. The reaction mixture was stirred at 65° C. for 1 hour, cooled and triturated with petroleum ether to give 10.3 g (38%) of ethyl 2,3-dihydro-2-oxo-4-trichloromethyl-5-thiazolecarboxylate, m.p. 109°-110° C. A mixture of 14.5 g (0.05 mole) of ethyl 2,3-dihydro-2-oxo-4-trichloromethyl-5-thiazolecarboxylate, 10.4 g (0.05 mole) of phosphorus pentachloride, and 100 ml. of phosphorus oxychloride was held at reflux for 7 days. Excess phosphorus oxychloride was removed under reduced pressure. The residue was treated with ice water and the aqueous mixture was extracted with ether. The ether solution was extracted with 10% sodium hydroxide, dried (CaSO₄) and concentrated under reduced pressure to give 3.2 g of oil which was chromatographed on silica gel using 5% ethyl acetate-petroleum ether as eluant. The first 1.2 l. of eluant gave 2.27 g of solid which was recrystallized from petroleum ether at low temperature to give 2.13 g (13.8%) of ethyl 2-chloro-4-trichloromethyl-5-thiazolecarboxylate, m.p. 42.5°-43.5° C.

Anal. Calc'd. for C₇ H₅ Cl₄ NO₂ S: C, 27.18; H, 1.62; N, 4.53; Cl, 45.86. Found: C, 27.27; H, 1.66; N, 4.53; Cl, 45.89.

Various esters may be prepared by reacting the compound of Example 11 with sodium hydroxide to form the free acid and then forming the acid chloride by reaction with thionyl chloride. Reaction of the acid chloride with an alcohol results in the desired ester.

EXAMPLE 15 Preparation of 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylic Acid.

A mixture of 116 g (0.4468 mole) of ethyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate, 18 g (0.45 mole) of sodium hydroxide, 200 ml. of water, 400 ml. of tetrahydrofuran was stirred at room temperature for 16 hours and made acidic with 50 ml. of concentrated hydrochloric acid. The reaction mixture was extracted twice with 200 ml. of ether. The ether-tetrahydrofuran solution was dried (MgSO₄) and concentrated under reduced pressure. The residual oil was treated with benzene and the benzene solution was concentrated under reduced pressure to remove the last trace of water. The residual solid was recrystallized from hexane-benzene to give 76 g (73.4%) of 2-chloro-4-trifluoromethyl-5-thiazolecarboxylic acid, m.p. 131°-131.5° C.

Anal. Calc'd. for C₅ H₁ ClF₃ NO₂ S: C, 25.92; H, 0.47; Cl, 15.31; N, 6.05. Found: C, 26.07; H, 0.52; Cl, 15.64; N, 6.10.

EXAMPLE 16 Preparation of 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylic Acid Chloride.

A mixture of 36.0 g (0.1554 mole) of the acid of Example 15 and 171 g (1.437 mole) of thionyl chloride were held at reflux for 6 hours. Excess thionyl chloride was removed under reduced pressure and the residue (38.1 g, 98%) was reacted as described in Examples 17-29.

EXAMPLE 17 Preparation of Isopropyl 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylate.

The acid chloride of Example 16 (5.2 g), and 10 g of isopropanol were held at reflux for 16 hours. Excess alcohol was removed under reduced pressure. The residue was dissolved in 50 ml. of ether. The ether solution was washed with sodium bicarbonate, dried (MgSO₄) and concentrated under reduced pressure. The crude product was distilled at 1 mm. on a Kugelrohr to give 4.9 g (86%) of the desired product as colorless liquid, n_(D) ²⁵ =1.4655.

Anal. Calc'd. for C₈ H₇ ClF₃ NO₂ S: C, 35.10; H, 2.58; N, 5.12; Cl, 12.96. Found: C, 35.15; H, 2.62; N, 5.11; Cl, 12.90.

EXAMPLE 18 Preparation of Benzyl 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylate.

The procedure of Example 17 was repeated utilizing benzyl alcohol in lieu of isopropanol to give 2.85 g of a white solid, m.p. 56°-58° C.

Anal. Calc'd. for C₁₂ H₇ ClF₃ NO₂ S: C, 44.80; H, 2.19; N, 4.35; Cl, 11.02. Found: C, 44.86; H, 2.19; N, 4.34; Cl, 11.09.

EXAMPLES 19-29

Utilizing the appropriate alcohol and the procedure of Example 17, the following compounds have been prepared.

2,2,2-Trichloroethyl 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylate, n_(D) ²⁵ =1.5094.

Anal. Calc'd. for C₇ H₇ Cl₄ F₃ NO₂ S: C, 23.16; H, 0.56; N, 3.86; Cl, 38.95. Found: C, 23.24; H, 0.62; N, 3.92; Cl, 38.96.

2-Butoxyethyl 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylate, n_(D) ²⁵ =1.4683.

Anal. Calc'd. for C₁₁ H₁₃ ClF₃ NO₂ S: C, 39.82; H, 3.95; N, 4.22; Cl, 10.68. Found: C, 40.07; H, 3.87; N, 4.22; Cl, 11,53.

2-Chloroethyl 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylate, n_(D) ²⁵ =1.4965.

Anal. Calc'd. for C₇ H₄ Cl₂ F₃ NO₂ S: C, 28.59; H, 1.37; N, 4.76; Cl, 24.11. Found: C, 28.67; H, 1.40; N, 4.76; Cl, 24.06.

n-Butyl 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylate, n_(D) ²⁵ =1.4685.

Anal. Calc'd. for C₉ H₉ ClF₃ NO₂ S: C, 37.57; H, 3.15; N, 4.87. Found: C, 37.54; H, 3.17; N, 4.90.

n-Hexyl 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylate, n_(D) ²⁵ =1.4657.

Anal. Calc'd. for C₁₁ H₁₃ ClF₃ NO₂ S: C, 41.84; H, 4.15; N, 4.44. Found: C, 41.86; H, 4.15; N, 4.43.

n-Octyl 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylate, n_(D) ²⁵ =1.4658.

Anal. Calc'd. for C₁₃ H₁₇ ClF₃ NO₂ S: C, 45.42; H, 4.98; N, 4.07. Found: C, 45.58; H, 5.05; N, 4.04.

Phenyl 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylate, n_(D) ²⁵ =1.5389.

Anal. Calc'd. for C₁₁ H₅ ClF₃ NO₂ S: C, 42.94; H, 1.64; N, 4.55. Found: C, 42.97; H, 1.67; N, 4.58.

p-Chlorophenyl 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylate, n_(D) ²⁵ =1.5552.

Anal. Calc'd. for C₁₁ H₄ Cl₂ F₃ NO₂ S: C, 38.60; H, 1.17; N, 4.09. Found: C, 39.08; H, 1.00. N, 4.09.

Allyl 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylate, b.p. 68° C. at 0.1 mm; n_(D) ²⁵ =1.4816.

Anal. Calc'd. for C₈ H₅ ClF₃ NO₂ S: C, 35.37; H, 1.86; N, 5.16. Found: C, 35.50; H, 1.93; N, 5.22.

Methyl 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylate. The residue was crystallized at low temperature from hexane to give 3.25 g (95%) of methyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate as light yellow prisms, m.p. 32°-34° C.

Anal. Calc'd. for C₆ H₃ F₃ NO₃ S: C, 31.72; H, 1.77; N, 6.17. Found: C, 31.88; H, 1.80; N, 6.20.

Propargyl 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylate.

A mixture of 4.63 g (0.02 mole) of 2-chloro-4-trifluoromethyl-5-thiazolecarboxylic acid, 2.42 g (0.02 mole) of propargyl bromide, 2.59 g (0.02 mole) of diisopropylamine, and 50 ml. of methylene chloride was stirred for 16 hours. The methylene chloride solution was washed successively with diluted hydrochloric acid and saturated sodium bicarbonate, dried (MgSO₄) and concentrated under reduced pressure. The residue was Kugelrohr distilled to give propargyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate as a colorless liquid.

Anal. Calc'd. for C₈ H₃ ClF₃ NO₂ S: C, 35.63; H, 1.12. Found: C, 35.59; H, 1.29.

The 2,4-disubstituted-5-thiazolecarboxylates of the invention may also be prepared in accordance with the following reaction scheme: ##STR3## In accordance with the above reaction scheme, ketoesters in chloroform are added dropwise to one equivalent of sulfuryl chloride. The reaction mixture is held at reflux for a number of hours and the chloroform removed under reduced pressure. An equimolar portion of the resultant 2-chloro-3-ketoester is added to thiourea in ethanol and held at reflux for 16-20 hours. Ethanol is then removed under reduced pressure and the residue neutralized with sodium bicarbonate solution to give a 2-amino-4-alkyl-5-thiazolecarboxylic acid ester. A solution of said ester in concentrated acid is diazotized at -5° to 30° C. with sodium nitrite. The resulting diazonium salt solution is poured into the corresponding cuprous halide or potassium iodide solution. After gas evolution has subsided, the reaction mixture is extracted with ether. The ether extract is dried and concentrated and the residue is purified by either Kugelrohr distillation at reduced pressure or by chromatography.

EXAMPLE 30 Preparation of Ethyl 2-Chloro-4-Ethyl-5-Thiazolecarboxylate

Ethyl 2-chloro-3-oxo-pentanoate is prepared from ethyl 3-oxo-pentanoate and sulfuryl chloride utilizing the procedure of Bankowski et al, Rocz. Chem., Volume 49, Page 1899 (1971). A mixture of 9.2 g (0.0515 mole) of ethyl 2-chloro-3-oxo-pentanoate, 3.92 g (0.0515 mole) of thiourea and 30 ml. of ethanol was held at reflux for 17 hours. Ethanol was removed under reduced pressure and the residue was treated with 300 ml. of saturated sodium bicarbonate solution. The solid precipitate was collected to give 11.2 g of white solid, m.p. 165°-170° C. which was recrystallized from ethanol to give 7.7 g (75%) of ethyl 2-amino-4-ethyl-5-thiazolecarboxylate as colorless prisms, m.p. 177°-179° C. To a solution of 7.0 g (0.0349 mole) of ethyl 2-amino-4-ethyl-5-thiazolecarboxylate and 0.2 g of CaSO₄ in 60 ml. of concentrated HCl was added dropwise a solution of NaNO₂ in 20 ml. of water in such a way that the reaction temperature did not exceed 30° C. The reaction mixture was stirred for 30 minutes and poured into a solution of 3.5 g (0.035 mole) of cuprous chloride in 30 ml. of 6 N HCl. The resulting dark blue solution was stirred for 30 minutes and extracted with ether. The ether solution was dried and concentrated under reduced pressure. The residue was Kugelrohr distilled at 2 mm. to give 4.35 g of yellow liquid which was chromatographed on silica gel to give 4.0 g (52%) of the desired product as colorless liquid, n_(D) ²⁵ =1.5189.

Anal. Calc'd. for C₈ H₁₀ ClNO₂ S: C, 43.73; H, 4.59; N, 6.38. Found: C, 43.88; H, 4.62; N, 6.34.

EXAMPLE 31 Preparation of Ethyl 2-Chloro-4-Isopropyl-5-Thiazolecarboxylate.

Ethyl 2-chloro-4-methyl-3-oxo-pentanoate is prepared in accordance with the literature procedure discussed in Example 30. A mixture of 15.0 g (0.0799 mole) of ethyl 2-chloro-4-methyl-3-oxo-pentanoate, 61 g (0.0802 mole) of thiourea and 60 ml. of ethanol was held at reflux for 21 hours. Ethanol was removed under reduced pressure and the residual oil was treated with 400 ml. of saturated sodium bicarbonate solution. The precipitate was collected to give 14.9 g of white solid, m.p. 172°-174° C., which was recrystallized from ethanol-water to give 13.6 g (82%) of ethyl 2-amino-4-isopropyl-5-thiazolecarboxylate as white prisms, m.p. 174°-178° C. A solution of 2.14 g (0.010 mole) of ethyl 2-amino-4-isopropyl-5-thiazolecarboxylate and 0.1 g of CaSO₄ in 40 ml. of concentrated hydrochloric acid was cooled with an ice bath. When the temperature of the reaction solution dropped below 10° C., the hydrochloride salt precipitated out of solution. The reaction mixture was allowed to warm to room temperature and the hydrochloride salt gradually dissolved again. To the above solution was added dropwise 1.0 g (0.0144 mole) of NaNO₂ in 10 ml. of water in 15 minutes. After completion of addition of the NaNO₂ solution, the reaction mixture was stirred for another 5 minutes. Cuprous chloride (1.0 g, 0.010 mole) was added to the above solution. A vigorous evolution of gas occurred. The dark blue mixture turned light blue after stirring for 5 minutes. The reaction mixture was extracted twice with 50 ml. of ether. The ether solution was washed successively with water, saturated sodium bicarbonate and saturated NaCl solution, dried (MgSO₄) and concentrated under reduced pressure to give 1.8 g of oil which was crystallized from hexane to give 0.05 g of 2,2'-bis-(ethyl 4-isopropyl-5-thiazolecarboxylate) as white needles, m.p. 192°-194° C.

The mother liquor was concentrated under reduced pressure and the residue was chromatographed on a silica gel column with Et₂ O-petroleum ether as eluant. The first fraction (using 1 l. of 1% ether-petroleum ether as eluant) contained 1.2 g of oil which was distilled on a Kugelrohr at 2 mm. (pot temperature 100°-120° C.) to give 1.15 g (49%) of ethyl 2-chloro-4-isopropyl-5-thiazolecarboxylate as a colorless liquid, n_(D) ²⁵ =1.5145.

Anal. Calc'd. for C₉ H₁₂ ClNO₂ S: C, 46.24; H, 5.18; N, 5.99. Found: C, 46.40; H, 5.22; N, 6.06.

EXAMPLE 32 Preparation of Ethyl 2-Chloro-4-t-Butyl-5-Thiazolecarboxylate.

Utilizing ethyl 2-chloro-4,4-dimethyl-3-oxo-pentanoate and the procedure of Example 31, ethyl 2-chloro-4-t-butyl-5-thiazolecarboxylate is prepared.

Anal. Calc'd. for C₁₀ H₁₄ ClNO₂ S: C, 48.48; H, 5.70; N, 5.56. Found: C, 48.41; H, 5.73; N, 5.62.

EXAMPLE 33 Preparation of Ethyl 2-Iodo-4-Trifluoromethyl-5-Thiazolecarboxylate.

To a cold (-5° C.) solution of 4.0 g (0.0166 mole) of ethyl 2-amino-4-trifluoromethyl-5-thiazolecarboxylate, prepared according to U.S. Pat. No. 2,726,237, in 30 ml. of 85% phosphoric acid and 30 ml. of 70% nitric acid was added a solution of 1.26 g (0.0166 mole) of sodium nitrite in 10 ml. of water in 10 minutes. The reaction mixture was stirred for 10 minutes and poured into a solution of 10 g of potassium iodide in 100 ml. of water. The reaction mixture was stirred overnight and extracted with ether. The ether solution was dried and concentrated and the residue was chromatographed on silica gel to give 1.5 g of the desired product, m.p. 75°-76° C.

Anal. Calc'd. for C₇ H₅ F₃ INO₃ S: C, 23.94; H, 1.44; N, 3.99; I, 36.15. Found: C, 23.93; H, 1.44; N, 3.95; I, 36.08.

EXAMPLE 34 Preparation of Ethyl 2-Bromo-4-Trifluoromethyl-5-Thiazolecarboxylate.

To a solution of 4.5 g (0.0187 mole) of ethyl 2-amino-4-trifluoromethyl-5-thiazolecarboxylate in 50 ml. of 85% phosphoric acid at -10° C. was added 25 ml. of nitric acid. To this mixture was added dropwise at -10° C. to -5° C. a solution of 4.0 g (0.0579 mole) of sodium nitrite in 20 ml. of water in 30 minutes. This mixture was stirred for 10 minutes at -10° C. to -5° C. and poured into a solution of 2.70 g (0.0187 mole) of freshly prepared cuprous bromide in 20 ml. of hydrobromic acid. A vigorous evolution of gas occurred. The reaction mixture was stirred for 5 minutes and diluted with water. The solid suspension was filtered and air-dried to give 4.8 g of solid which was chromatographed on silica gel using ether/petroleum ether (1:4) as eluant. The first 1 liter of eluate gave 3.7 g of solid which was recrystallized from petroleum ether to give 2.9 g (51%) of the desired product as white needles, m.p. 75.5°-76.5° C.

Anal. Calc'd. for C₇ H₅ BrF₃ NO₂ S: C, 27.64; H, 1.66; N, 4.61; Br, 26.28. Found: C, 27.65; H, 1.65; N, 4.61; Br, 26.27.

EXAMPLE 35 Preparation of Ethyl 2-Fluoro-4-Trifluoromethyl-5-Thiazolecarboxylate.

A mixture of 26 g (0.1 mole) of ethyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate, 37 g (0.55 mole) of potassium fluoride, and 0.11 g of 1,4,7,10,13,16-hexaoxacyclooctadecane (18-CROWN-6, Aldrich Chemical Company) was held at reflux for 23 hours. Since an analysis showed the reaction to be incomplete, another 45 g (0.77 mole) of potassium fluoride was added and the reaction mixture held at reflux for 64 hours. To said mixture, 0.15 g of 18-CROWN-6 and an additional 27 g (0.40 mole) of potassium was added and held at reflux for 22 hours. Due to poor cooling overnight some of the solvent had evaporated. The reaction mixture was cooled and 300 ml. of acetonitrile added. The acetonitrile was filtered and concentrated. The residue was Kugelrohr distilled to give 13.7 g of a material which was separated by spinning band column at 15 mm Hg to give 4.2 g of the desired product, n_(D) ²⁴ =1.4348.

Thiazolecarboxylates of the invention in which X is lower alkoxy or phenoxy or substituted phenoxy may be prepared by reacting the halogenated analogue with sodium alkoxide or phenol in the presence of potassium carbonate.

EXAMPLE 36 Preparation of Ethyl 2-Phenoxy-4-Trifluoromethyl-5-Thiazolecarboxylate.

A mixture of 5.2 g (0.02 mole) of ethyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate, 1.88 g (0.02 mole) of phenol, 2.76 g (0.02 mole) of K₂ CO₃ and 50 ml. of acetone was held at reflux for 3 days. Acetone was removed under reduced pressure. The residue was treated with water, extracted with ether. The ether solution was dried (MgSO₄) and concentrated under reduced pressure. The residual solid was heated with hexane, cooled and filtered to give 4.8 g (76%) of the desired product, m.p. 52°-54° C.

Anal. Calc'd. for C₁₃ H₁₀ F₃ NO₂ S: C, 49.21; H, 3.18; N, 4.41. Found: C, 49.27; H, 3.19; N, 4.38.

EXAMPLE 37 Preparation of Ethyl 2-Ethoxy-4-Triethoxymethyl-5-Thiazolecarboxylate.

To a warm solution of sodium ethoxide prepared from 2.0 g (0.0869 mole) of Na and 50 ml. of ethanol was added 5.2 g (0.02 mole) of ethyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate. The mixture was stirred for 4 hours. Ethanol was removed under reduced pressure. The residue was treated with water and extracted with ether. The ether solution was washed with saturated sodium bicarbonate, dried (MgSO₄) and concentrated under reduced pressure. The residue was distilled to give 2.2 g of the desired product as an oil, b.p. 115° C. at 0.1 mm; n_(D) ²⁵ =1.4776.

Anal. Calc'd. for C₁₅ H₂₅ NO₆ S: C, 51.86; H, 7.25; N, 4.03. Found: C, 51.36; H, 7.03; N, 4.57.

EXAMPLE 38 Preparation of Ethyl 2-Ethoxy-4-Trifluoromethyl-5-Thiazolecarboxylate.

To a cold (0° C.) solution of sodium ethoxide, prepared from 0.46 g (0.02 mole) of sodium and 40 ml. of dried ethanol, was added 5.2 g (0.02 mole) of ethyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate. A precipitate formed immediately. The reaction mixture was heated to 80° C. and then poured into ice water. The precipitate was collected to give 4.2 g (78%) of the desired product as a white solid, m.p. 30.5°-31.5° C.

Anal. Calc'd. for C₉ H₁₀ F₃ NO₃ S: C, 40.15; H, 3.74; N, 5.20. Found: C, 40.11; H, 3.75; N, 5.19.

EXAMPLE 39 Preparation of Ethyl 2-(2',4'-Dichlorophenoxy)-4-Methyl-5-Thiazolecarboxylate.

A mixture of 6.24 g (0.03 mole) of ethyl 2-chloro-4-methyl-5-thiazolecarboxylate, 4.89 g (0.03 mole) of 2,4-dichlorophenol, 4.14 g (0.03 mole) of potassium carbonate and 40 ml. of acetone was held at reflux for 89 hours. Acetone was removed under reduced pressure. The residue was treated with 50 ml. of water and extracted with ether. The ether solution was washed successively with saturated sodium bicarbonate, 30 ml. of 10% sodium hydroxide and 50 ml. of water. The ether solution was dried (MgSO₄) and concentrated. The residue was recrystallized from hexane to give 5.8 g (58%) of ethyl 2-(2',4'-dichlorophenoxy)-4-methyl-5-thiazolecarboxylate as a white solid, m.p. 71°-73° C.

Anal. Calc'd. for C₁₃ H₁₁ Cl₂ NO₃ S: C, 47.00; H, 3.34; N, 4.22; Cl, 21.34. Found: C, 47.04; H, 3.34; N, 4.21; Cl, 21.36.

Amides are prepared by reacting the appropriate acid chloride with the appropriate amine.

EXAMPLE 40 Preparation of N,N-Diethyl-2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxamide.

To a well-stirred solution of 4.0 g (0.0160 mole) of the acid chloride of Example 16 in 20 ml. of ether was added dropwise 2.34 g (0.032 mole) of diethylamine in 5 ml. of ether. The insoluble salt was filtered. The ether solution was washed with water, dried and concentrated under reduced pressure. The residue was crystallized from hexane at low temperature to give 4.1 g of the desired product, m.p. 40°-41° C.

Anal. Calc'd. for C₉ H₁₀ ClF₃ N₂ OS: C, 37.70; H, 3.51; N, 9.77; Cl, 12.38. Found: C, 37.66; H, 3.53; N, 9.78; Cl, 12.33.

Salts may be prepared by reaction of the free acid with the appropriate base.

EXAMPLE 41 Preparation of Sodium Salt of 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylic Acid, Monohydrate.

A mixture of 116 g (0.4468 mole) of ethyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate, 18 g (0.45 mole) of sodium hydroxide, 200 ml. of water and 400 ml. of tetrahydrofuran was stirred at room temperature for 16 hours. The aqueous solution was concentrated and dried under vacuum to give the sodium salt of 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate, monohydrate as a white solid, m.p. 211°-215° C.

Anal. Calc'd. for C₅ H₂ ClF₃ NO₃ S: C, 22.10; H, 0.74; N, 5.16. Found: C, 22.14; H, 0.71; N, 5.21.

EXAMPLE 42 Preparation of Triethanolamine Salt of 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylic Acid.

To a cold (5° C.) solution of 6.93 g (0.03 mole) of 2-chloro-4-trifluoromethyl-5-thiazolecarboxylic acid in 20 ml. of ether was added 4.47 g (0.03 mole) of triethanolamine. The reaction mixture was stirred at room temperature for 18 hours and filtered to give 8.78 g (77%) of the desired product, m.p. 101°-102° C.

Anal. Calc'd. for C₁₁ H₁₆ ClF₃ N₂ O₅ S: C, 34.69; H, 4.23; N, 7.36. Found: C, 34.89; H, 4.07; N, 7.39.

EXAMPLE 43 Preparation of Isopropylamine Salt of 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylic Acid.

To a cold (6° C.) solution of 4.55 g (0.0196 mole) of the free acid in 20 ml. of ether was added dropwise a solution of 1.16 g (0.0196 mole) of isopropylamine in 10 ml. of ether. The reaction mixture was stirred at room temperature for 1 hour and the white precipitate was filtered to give 5.50 g (96.5%) of the desired product, m.p. 132°-134° C.

Anal. Calc'd. for C₈ H₁₀ ClF₃ N₂ O₂ S: C, 33.05; H, 3.47; N, 9.64. Found: C, 33.47; H, 3.55; N, 9.72.

EXAMPLE 44 Preparation of Diethylamine Salt of 2-Chloro-4-Trifluoromethyl-5-Thiazolecarboxylic Acid.

To a cold (6° C.) solution of 6.93 g (0.03 mole) of the free acid in 20 ml. of ether was added 2.19 g (0.03 mole) of diethylamine in 100 ml. of ether. The precipitate, which formed immediately, was filtered to give 7.95 g (86.4%) of the desired product, m.p. 131°-132° C.

Anal. Calc'd. for C₉ H₁₂ ClF₃ N₂ O₂ S: C, 35.47; H, 3.97; N, 9.20. Found: C, 35.60; H, 3.97; N, 9.21.

In accordance with the novel aspects of the present invention, the thiazolecarboxylates have been found to be effective in reducing herbicidal injury to selected crop plants due to application of acetamide herbicides. A preferred embodiment are those thiazolecarboxylates substituted in the 4-position with a trifluoromethyl moiety. Such compounds have been found to be quite superior in their ability to reduce herbicidal injury. As illustrated in Table IX, thiazolecarboxylates substituted by a trifluoromethyl in the 4-position are clearly superior to those substituted in the 4-position by methyl in reducing herbicidal injury to sorghum. Another preferred group of thiazolecarboxylates are those substituted in the 2-position with a halogen, especially chloro. Most preferred are those thiazole alkyl esters of the thiazolecarboxylic acid having a chloro in the 2-position and a trifluoromethyl in the 4-position.

While the compounds of the invention generally tend to safen rice and sorghum crops to the herbicidal effects of acetamide herbicides, especially acetanilide herbicides, those skilled in the art will appreciate that the compounds of the invention may be used most effectively in safening sorghum against injury due to alachlor and 2-chloro-N-(2-methoxy-1-methylethyl)-6'-ethyl-o-acetotoluidide, especially alachlor, and rice, especially direct-seeded rice, against the herbicidal effects of butachlor.

Although this invention has been described with respect to specific modifications, the details thereof are not to be construed as limitations, for it will be apparent that various equivalents, changes and modifications may be resorted to without departing from the spirit and scope thereof and it is understood that such equivalent embodiments are intended to be included herein. 

What is claimed is:
 1. A compound having the formula ##STR4## wherein n is zero or one; X is selected from the group consisting of chloro, bromo, iodo, fluoro, lower alkoxy, phenoxy and phenoxy substituted by one or two groups independently selected from the group consisting of lower alkyl and halogen; R is selected from the group consisting of alkyl having up to five carbon atoms wherein at least one hydrogen atom has been replaced by a halogen atom and triethoxymethyl; when n is one, R' is selected from the group consisting of hydrogen, agriculturally acceptable cations, alkyl having from one to ten carbon atoms, lower alkenyl, lower alkynyl, lower alkoxy lower alkyl, alkyl having up to five carbon atoms wherein at least one hydrogen atom has been replaced by a halogen atom, benzyl, phenyl and phenyl substituted by one or two members selected from the group consisting of halogen, lower alkyl, trifluoromethyl and nitro; when n is zero, R' is selected from the group consisting of chloro, amino and mono or di-lower alkyl amino.
 2. A compound according to claim 1 wherein n is one.
 3. A compound according to claim 1 wherein n is zero.
 4. A compound according to claim 2 wherein X is chloro.
 5. A compound according to claim 2 wherein R is alkyl having up to five carbon atoms wherein at least one hydrogen atom has been replaced by a halogen atom.
 6. A compound according to claim 5 wherein R is trifluoromethyl.
 7. A compound according to claim 2 wherein R' is hydrogen, alkyl having from one to ten carbon atoms, lower alkenyl, lower alkynyl, lower alkoxy lower alkyl, alkyl having up to five carbon atoms wherein at least one hydrogen atom has been replaced by a halogen atom, benzyl, phenyl or phenyl substituted by one or two members selected from the group consisting of halogen, lower alkyl, trifluoromethyl and nitro.
 8. A compound according to claim 2 wherein R' is hydrogen, alkyl having from one to ten carbon atoms, benzyl, phenyl or phenyl substituted by one member selected from the group consisting of halogen, lower alkyl, trifluoromethyl and nitro.
 9. A compound according to claim 2 wherein R' is alkyl having from one to ten carbon atoms.
 10. A compound according to claim 2 wherein X is halogen, R is alkyl having up to five carbon atoms wherein at least one hydrogen atom has been replaced by a halogen atom and R' is alkyl having from one to ten carbon atoms.
 11. A compound according to claim 10 wherein X is chloro and R is trifluoromethyl.
 12. A compound according to claim 2 wherein X is halogen, R is alkyl having up to five carbon atoms wherein at least one hydrogen atom has been replaced by a halogen atom and R' is benzyl.
 13. A compound according to claim 12 wherein R is trifluoromethyl.
 14. A compound according to claim 2 wherein X is halogen, R is alkyl having up to five carbon atoms wherein at least one hydrogen atom has been replaced by a halogen atom and R' is phenyl or phenyl substituted by halogen.
 15. A compound according to claim 1 in which said compound is butyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate.
 16. A compound according to claim 1 in which said compound is hexyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate.
 17. A compound according to claim 1 in which said compound is octyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate.
 18. A compound according to claim 1 in which said compound is ethyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate.
 19. A compound according to claim 1 in which said compound is phenyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate.
 20. A compound according to claim 1 in which said compound is p-chlorophenyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate.
 21. A compound according to claim 1 in which said compound is benzyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate.
 22. A compound according to claim 1 in which said compound is 2-chloro-4-trifluoromethyl-5-thiazolecarboxylic acid.
 23. A compound according to claim 1 in which said compound is the α-methylethanamine salt of 2-chloro-4-trifluoromethyl-5-thiazolecarboxylic acid.
 24. A compound according to claim 1 in which said compound is allyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate.
 25. A compound according to claim 1 in which said compound is methyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate.
 26. A compound according to claim 1 in which said compound is isopropyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate.
 27. A compound according to claim 1 in which said compound is butoxyethyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate.
 28. A compound according to claim 1 in which said compound is β-trichloroethyl 2-chloro-4-trifluoromethyl-5-thiazolecarboxylate. 